WHO/BS/2014.2244 ENGLISH ONLY EXPERT COMMITTEE ON ...

WHO/BS/2014.2244

ENGLISH ONLY

EXPERT COMMITTEE ON BIOLOGICAL STANDARDIZATION

Geneva, 13 to 17 October 2014

COLLABORATIVE STUDY ON THE 1st INTERNATIONAL REFERENCE PANEL (PLASMA)

FOR LUPUS ANTICOAGULANT

Helen Wilmot and Elaine Gray

1

Haemostasis Section,

National Institute for Biological Standards and Control

Potters Bar, Hertfordshire, EN6 3QG, UK 1Principal Investigator

NOTE:

This document has been prepared for the purpose of inviting comments and suggestions on the

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should be addressed to the World Health Organization, 1211 Geneva 27, Switzerland, attention:

Technologies, Standards and Norms (TSN). Comments may also be submitted electronically to

the Responsible Officer: Dr David Wood at email: [email protected].

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WHO/BS/2014.2244

Summary Nineteen laboratories from 11 different countries participated in a collaborative study to evaluate

3 plasma samples as the 1st International Reference Panel (Plasma) Lupus anticoagulant, 13/172.

The candidates were prepared by titration of lupus negative and lupus positive patient plasmas to

obtain a negative (12/148), a moderate positive (12/150) and a strong positive (12/152) lupus

anticoagulant samples. Another lupus positive plasma sample, 96/560, was also included in the

study.

Nineteen laboratories returned 22 sets of data for dilute Russell Viper’s venom time (dRVVT),

13 laboratories returned 21 sets of data for activated partial thromboplastin time (APTT), 4

laboratories returned results for silica clotting time (SCT), 2 laboratories returned data for dilute

Prothrombin time (dPT), while one set of result was returned for kaolin clotting time (KCT),

activated seven lupus anticoagulant assay (ASLA) and Taipan snake venom time (TSVT). The

laboratories performed screening tests and, where appropriate, confirmation and mixing studies

for each method.

The intra-laboratory variability was low. The majority of laboratories obtained ratios that had

intra-laboratory coefficients of variation (CV) of less than 5% when the test samples were

calculated relative to the local pooled normal plasma (PNP) indicating that the participants

performed assays for lupus anticoagulant reproducibly and with high precision.

Inter-laboratory variability was low for dRVVT, but higher for the other assay methods. Both

intra- and inter-laboratory variation were reduced when the ratios were recalculated relative to

sample A, 12/148, the candidate lupus negative plasma.

All methods employed in this study found 12/148 to be lupus negative and both 12/150 and

12/152 to be lupus positive. The other lupus positive plasma, 96/560 was also confirmed as

lupus positive. The ranking order of lupus positivity for the 3 lupus positive samples in all the

assays were C>B>Z.

The results of this study confirmed the lupus status of the 3 candidates and it is therefore

recommended that all 3 plasmas be established as:

The 1st International Reference Panel (Plasma) for Lupus Anticoagulant, 13/172, with the

following components:

12/148 Lupus negative

12/150 Lupus moderate positive

12/152 Lupus strong positive

WHO/BS/2014.2244

Introduction The presence of antiphospholipid antibodies characterises Lupus Anticoagulant. These

immunoglobulins are heterogeneous and bind to phospholipid, disrupting the clotting process

and leading to a prolonged clotting time in vitro tests. However, the clinical manifestations are

occurrence and recurrence of thrombotic events rather than bleeding issues. Lupus

anticoagulant positivity also carries increased risk of recurrent spontaneous miscarriages, foetal

death and foetal retardation. Patients require long-term anticoagulant therapy and clotting assay

based laboratory tests are employed to help clinical decision on diagnosis and treatment regimen.

Diagnosis is difficult as patients with a clotting factor deficiency also have prolonged clotting

times. Although mixing studies are performed to identify if the clotting time is restored by

normal plasma (indicating factor deficiency) or by washed platelets (phospholipid), indicating

the presence of antiphospholipid antibodies, there is no specific test for lupus and therefore

misdiagnosis is common as full correction is not always observed. There are national and

international guidelines on laboratory testing for lupus anticoagulants (1, 2). Numerous studies,

including quality assessment schemes illustrate large numbers of false negative and positive

diagnoses are still an issue (3, 4, 5, 6, 7, 8). The use of appropriate reference materials have been

recommended by lupus testing guidelines as means of improving the quality of testing. The 1st

British Reference Panel(Plasma) for Lupus Anticoagulant was established by NIBSC in 1999

and proven to be valuable in helping laboratories to improve assay performance of lupus

anticoagulant tests. The stock of this panel was deleted within 5 years of its establishment and

there is no replacement available. Currently there is no international reference material for

Lupus Anticoagulant. This study serves to evaluate the proposed 1st International Reference

Panel(Plasma) for Lupus Anticoagulant.

Participants Nineteen laboratories from 11 different countries (1 Australia, 1 Austria, 1 Belgium, 1 Canada, 1

France, 1 Germany, 2 Italy, 1 Japan, 1 The Netherlands, 5 UK, 4 USA) agreed to participate in

the study, all of which returned data in time for the statistical analysis.

The participants included 6 clinical laboratories, 8 diagnostics manufacturers, 4 academic

laboratories and 1 regulatory authority. A list of participants is given in Appendix 1 at the end of

this report. Each laboratory is referred to in this report by an arbitrarily assigned number, not

necessarily representing the order of listing in the Appendix.

Samples The following coded samples were sent to each participant:

A Proposed 1st International Reference Panel (Plasma) for Lupus Anticoagulant, Negative

plasma (12/148)

B Proposed 1st International Reference Panel(Plasma) for Lupus Anticoagulant, Moderate

positive plasma (12/150)

C Proposed 1st International Reference Panel (Plasma) for Lupus Anticoagulant, Strong

positive plasma (12/152)

Z 1st British Reference Plasma Panel for Lupus Anticoagulant, Weak positive Plasma

(96/560)

WHO/BS/2014.2244

The Candidates, 12/148 (lupus negative), 12/150 (lupus moderate)

and 12/152 (lupus positive) Samples A, B and C were freshly prepared at NIBSC from frozen platelet poor normal plasma

and platelet poor positive plasma. All donations had been tested and found to be virology

negative for HIV1&2, Hepatitis B surface antigen and Hepatitis C. The negative pool was made

using plasma from a total of 10 donors and the positive pool was made using plasma from a total

of 17 donors. Each pool had HEPES added to a total of 0.8% w/v. The positive pool was diluted

1:1 in negative plasma to generate sample C (strong positive pool) and 1:3.3 to generate sample

B (moderate positive). The remaining negative plasma served as sample A (lupus negative). All

3 preparations were filled and freeze-dried into siliconised ampoules at NIBSC and stored at -

20°C. Stocks were sufficient to generate approximately 2500 ampoules of each preparation.

Product characteristics are shown in the tables below:

NIBSC Code 12/148

Presentation Sealed, siliconised glass 3 ml DIN

ampoules

Filling date 21st June 2012

Number of Ampoules available 2933

Liquid filling weight (g) (n=132, measurements taken

from all 3 pumps throughout the duration of the fill) 1.0087

CV of fill mass (%) 0.259

Homogeneity of the fill by activity: 3 ampoules

selected from the beginning, middle and end of the fill

were assayed by DRVVT method (duplicate

measurements for each). Effect of fill position was

assessed by ANOVA.

Screen/confirm

ratio (%CV) p

DRVVT 1.09 (4.02) 0.903

Mean dry weight (g) (n=6) 0.0830 (CV 0.62%)

Mean head space oxygen (%) (n=12) 0.48 (CV 57.80%)

Residual moisture (%) (n=12) 0.52 (CV 19.74%)

pH of plasma Pre-fill: 6.9, freeze-dried 7.8

Storage temperature -20°C

Address of processing facility NIBSC, Potters Bar, EN6 3QG, UK

Address of present custodian NIBSC, Potters Bar, EN6 3QG, UK

NIBSC Code 12/150


ampoules










assessed by ANOVA.

Screen/confirm

ratio (%CV) p

DRVVT 1.51 (3.72) 0.800

WHO/BS/2014.2244








NIBSC Code 12/152


ampoules










assessed by ANOVA.

Screen/confirm

ratio (%CV) p

DRVVT 1.71 (4.35) 0.581








A clotting factor screen was carried out on each freeze-dried preparation, where possible using

methods insensitive to the presence of lupus anticoagulant. The results are shown in Table 1.

Table 1: Clotting factor screen of 12/148, 12/150 and 12/152

Clotting factor IU/ml (95% confidence intervals)

12/148 12/150 12/152

FII 0.93

(0.87-1.00)

0.84

(0.78-0.90)

0.74

(0.69-0.79)

FV 0.78

(0.74-0.82)

0.79

(0.75-0.83)

0.87

(0.83-0.92)

FVII 0.90

(0.82-0.99)

0.80

(0.73-0.88)

0.75

(0.68-0.83)

FVIII 1.06

(1.02-1.11)

1.07

(1.03-1.12)

1.02

(0.98-1.06)

FIX 0.89

(0.82-0.97)

0.80

(0.73-0.86)

0.74

(0.69-0.81)

FX 0.96

(0.92-1.01)

0.85

(0.82-0.89)

0.73

(0.70-0.77)

Antithrombin Activity 0.97

(0.94-1.02)

0.96

(0.92-1.00)

0.94

(0.90-0.97)

WHO/BS/2014.2244

Antithrombin Antigen 1.02

(0.99-1.05)

0.92

(0.90-0.95)

0.94

(0.91-0.97)

Protein C 1.06

(1.02-1.10)

0.98

(0.95-1.01)

0.90

(0.87-0.93)

Free Protein S Antigen 0.93

(0.90-0.96)

0.86

(0.83-0.89)

0.79

(0.77-0.82)

Protein S functional activity 0.94

(0.89-1.00)

0.82

(0.78-0.87)

0.75

(0.71-0.80)

Assays for FII, V, VII and X were performed using tissue factor-based assays; FVIII and FIX

assays were performed using chromogenic kits, antithrombin assays were chromogenic (activity)

and latex bead-based (antigen); protein C assays were chromogenic, and protein S antigen was

latex bead-based, with protein S activity APTT-based. Although the protein S activity assay was

APTT-based, the assay involves dilution of the test sample in normal plasma and involves

activation of protein S, thus the contribution of lupus anticoagulant to the result is likely to be

small.

Study design and assay methods Participants were requested to carry out three independent assays of each chosen method(s) using

freshly reconstituted ampoules of samples A, B, C, and Z. Each set of assays was to be carried

out on separate days.

Each participant performed their routine in-house dilute Russell’s Viper Venom Time (dRVVT)

method(s) for Lupus Anticoagulant, plus any additional routine in-house tests (e.g. Activated

Partial Thromboplastin Time, Silica Clotting Time, Kaolin Clotting Time etc.). A list of

reagents, methods and instruments used by the participants is given in Appendix 2, together with

details of positive and negative controls used by each laboratory.

All 19 laboratories performed dRVVT, 13 performed Activation Partial Thromboplastin Time

(APTT), 4 performed Silica Clotting Time (SCT), 2 performed dilute Prothrombin Time (dPT), 1

lab performed Kaolin Clotting Time (KCT), 1 lab performed Activated Seven Lupus

Anticoagulant assay (ASLA), 1 performed the Taipan Snake Venom Time (TSVT), with Ecarin

time as confirmation test, and one performed an anti-cardiolipin (aCL) enzyme linked

immunosorbent assay (ELISA). Mixing study regimes for all the clot-based assays when

performed were as indicated in Appendix 2.

Raw assay data were returned to NIBSC together with calculated ratios where appropriate (e.g.

dRVVT screen/confirm ratios) for each participant. NIBSC calculated ratios for each individual

laboratory (where possible) are shown in Appendix 3. Where it was not possible to analyse

results centrally at NIBSC (e.g. where mix only results were returned), then the laboratory’s

reported data are shown. The collaborative study protocol is shown in Appendix 4.

Analysis of data An independent calculation of ratios from raw data and statistical analysis of ratios were

performed at NIBSC. Screen, confirm and mix ratios were calculated relative to local pooled

normal plasma (PNP) and the candidate Lupus negative plasma, Sample A (12/148). The

formulae used for calculation of the ratios are as shown in Table 2. For each sample, duplicate

clotting times from each individual assay were used to calculate the mean clotting times which

were then used to calculate ratios for each individual assay. Laboratory mean ratios for each

WHO/BS/2014.2244

independent assay were combined to give overall laboratory mean ratios and intra-laboratory

variability was expressed as % coefficient of variation (CV). Where there were sufficient

numbers of data sets for each method, overall mean ratios for each method and inter-laboratory

variation (%CV) were calculated from overall individual laboratory mean and this was carried

out for dRVVT and APTT.

Table 2: Calculation of ratios for different assay methods

dRVVT, SCT, dPT, ASLA, TSVT

Screen ratio test screen clotting time/PNP screen clotting time or sample A screen

clotting time

Confirm ratio test confirm clotting time/PNP confirm clotting time or sample A confirm

clotting time

Screen/ Confirm

ratio test screen clotting time/test confirm clotting time

Normalised

ratio (NR) screen ratio/confirm ratio

% correction of

ratio ((Screen ratio – confirm ratio)/Screen ratio)x100

Mix ratio test mix clotting time/PNP screen clotting time or sample A screen clotting

time

APTT


clotting time


time

KCT


clotting time


time

Rosner Ratio= (KCT-mix - KCT-PNP) / KCT-sample.

Results Some laboratories performed more than one type of assay for each method and the data from

each type of assay were treated as separate sets of results and, for example, referred to Lab 18a

and Lab 18b.

Nineteen laboratories returned 22 sets of data for dRVVT, with Lab 8 returning 3 sets of results

and Lab 18 returning 2 sets of results employing different dRVVT methods.

Thirteen laboratories returned 21 sets of data for APTT, with Lab 8 returning 6 sets of data, each

set using different APTT reagents and instruments, and Lab 11, 15 and 19 returning 2 sets of

results using different APTT reagents.

Four laboratories returned results for SCT, 2 laboratories returned data for dPT, while one set of

results each were returned for KCT, ASLA, TSVT and aCL.

WHO/BS/2014.2244

With the exception of the following, all the laboratories returned full set of results with

duplicates clotting times for each sample:

DRVVT:

Lab 1: Day 3; no results for sample C confirm.

Lab 3: No local positive control.

Lab 4: Mix results only; data cannot be interpreted in the usual manner.

Lab 6: No mix results reported for days 1 or 2. Day 3 mix results reported for B, C and Z

only.

Lab 8b: Day 1 – no duplicates reported. Day 2 – no duplicates for sample A screen or

confirm.

Lab 10: No duplicates for PNP or local positive screen or confirm (days 1, 2 or 3).

Lab 12: Uses Vipera lebetina venom instead of Russell’s viper venom.

Lab 13: No results for PNP confirm or sample A mix confirm (days 1, 2 or 3)

Lab 19: no results for sample A confirm days 2 and 3; no results for Z confirm day 3

APTT:

Lab 4: Mix results only; data cannot be interpreted in the usual manner.

Lab 5: No duplicates for mix results for A, B, C or Z on days 1 and 3. On day 3, no

duplicates for mix results for B, C or Z and no mix results for sample A.

Lab 6: Day 1 – no mix results reported. Days 2 and 3, mix results reported for samples B,

C and Z only.

Lab 8a: No confirm or mix for Actin FSL (8a1) or Pathromtin (8a2).

Lab 8b: No confirm or mix for Actin FSL (8a1) or Pathromtin (8a2).

Lab 8c: No confirm or mix for Actin FSL (8a1) or Pathromtin (8a2).

Lab 9: Mixes at 50:50 and 80:520 ratios for samples B, C and Z only.

Lab 11b: Mix results only for STAclot LA.

Lab 15a and b: No mix results reported.

Lab 17: Uses LCA index for APTT results so cannot be analysed alongside the other

APTT results.

Lab 19: Mix results only. Cannot analyse results against sample A as no screen results

reported for sample A.

SCT:

Lab 2: no mix results.

Lab 5: No mix results for sample A.

Lab 13: No PNP confirm, no confirm or mix for sample A, no duplicate confirm for

sample Z.

Lab 14: No duplicate for local positive confirm on day 2.

dPT:

Lab 18: Day 1– no duplicate for sample B confirm. 50:50 mix carried out for screen

reagent on positive samples only each day.

ASLA:

Lab 6: Mix carried out for samples A, B, C and Z on day 1 only.

TSVT:

Lab 6: Days 1 & 2 – no confirm test carried out for samples A or Z

WHO/BS/2014.2244

Ratios calculated for each independent assay, carried out by individual laboratories, using

different assay methods are presented in Appendix 3. Where analysis was not possible (e.g. mix

results only reported), then the results as reported by the originating laboratory are shown.

DRVVT The revised ISTH guidelines for lupus anticoagulant detection (Pengo et al., 2009) provide

information on how to obtain local cut-off values, but does not give “common” cut-off values for

any lupus anticoagulant assays. The BCSH guidelines (Greaves et al., 2000) for dRVVT stated

that the upper limit of normal ratio should be between 1.1 –1.2. DRVVT ratios of >1.1 should

be retested using the Platelet Correction Procedure (PCP) and a significant shortening (10%) of

the DRVVT is suggestive of the presence of lupus anticoagulant. A 50% normal to 50% test

mixture giving a ratio of more than 1.1 with DRVVT is also suggestive of the presence of lupus

anticoagulant.

Screen ratios, confirm ratios, normalised ratios, % correction of ratio and mix and screen ratios

were calculated relative to local pooled normal plasma (PNP) for Samples A, B, C and Z and

these are presented in Tables 3, 4, 5 and 6 respectively. When compared against the local PNP,

with the exception of Lab 12, sample A (12/148), the candidate negative plasma was found to be

negative by all the participants, with all screen ratios being close to 1 (overall mean ratio: 1.00,

range: 0.90 – 1.29). The screen ratio for Lab 12 was 1.29 and was slightly higher than the limit

of 1.2 as stated by the BCSH guidelines. However, the laboratory’s own cut off value was

reported to be 1.3 and therefore sample A would deem to be negative. For sample B (12/150),

the candidate moderate positive plasma and sample C (12/152), the strong positive plasma,

screen ratios were all greater than 1.2, with mean screen ratios of 1.51 (range: 1.31 – 1.93) and

1.86 (range 1.51 – 2.31) for samples B and C respectively. The results for confirm ratios and

normalised ratios, together with greater than 30% correction of ratio in majority of cases indicate

that both samples B and C are lupus positive, with sample C stronger than sample B. The mix

ratios for both samples B and C were also greater than 1.1 thus supporting lupus positivity status

of these materials. Sample Z is a weak positive sample and is not part of the proposed reference

panel for Lupus anticoagulant. The screen (mean 1.36, range 1.10 -1.79), confirm (mean 0.99,

range 0.93 – 1.17) and normalised (mean 1.38, range 1.14 – 1.70) ratios verified sample Z as

lupus positive. All laboratories obtained the same order of positivity for samples B, C, Z

(C>B>Z), indicating that all the test methods were able to correctly distinguish the activity of

these lupus positive samples. The intra-laboratory variability for dRVVT ratios relative to PNP

are shown in Tables 7, 8, 9 and 10 which present the %CV for screen, confirm and normalised

ratios for all 4 samples. It is clear that the majority of the participants were able to perform

dRVVT with good precision as the majority of the CVs was less than 5%.

Tables 4, 5 and 6 also present the calculated ratios for samples, B, C and Z relative to sample A

and it is encouraging that the ratios were similar to those obtained relative to the local PNP.

Table 11 shows direct comparison of the ratios and the %CVs for samples B, C and Z relative to

PNP or sample A and there is a clear improvement to inter-laboratory agreement for all the ratios

calculated when sample A was used.

WHO/BS/2014.2244

Table 3: dRVVT Screen ratios, confirm ratios, normalised ratios, % correction of ratio and mix

and screen ratios calculated relative to local pooled normal plasma (PNP) for sample A

Against Laboratory PNP

Lab Screen ratio Confirm

ratio NR

%

correction

of ratio

Mix/Screen Screen/

confirm ratio

1 0.94 0.88 1.06 5.91 NA 1.02

2 0.94 0.94 1.00 -4.21 NA 1.02

3 0.99 0.93 1.06 5.75 NA 1.08

4 NA NA NA NA NA

5 1.02 1.04 0.98 -2.40 NA 1.04

6 1.04 0.96 1.08 7.17 NA 1.14

7 0.91 0.85 1.08 7.17 0.85 1.04

8a 0.97 0.96 1.02 1.77 NA 1.07

8b 1.00 0.98 1.02 2.09 NA 0.95

8c 1.01 0.98 1.02 2.22 NA 1.09

9 1.05 1.05 1.00 -0.19 1.01 1.06

10 0.98 0.97 1.01 0.52 0.97 1.10

11 1.09 1.03 1.06 5.66 1.05 1.09

12 1.29 1.09 1.18 15.10 NA 1.38

13 0.98 NA NA NA NA NA

14 1.02 1.02 1.00 0.24 0.99 1.08

15 0.91 0.90 1.01 1.42 - 0.97

16 0.93 0.98 0.95 -4.86 0.99 1.10

17 1.00 0.83 1.21 16.94 - 1.21

18a 1.07 1.03 1.05 4.04 1.03 0.93

18b 0.90 0.95 0.95 -4.85 0.93 1.05

19 1.02 1.02 1.03 3.23 NA 1.03

Mean 1.00 0.97 1.04 3.14 0.98 1.07

Range 0.90-1.29 0.85-1.09 0.95-1.21 -4.86-16.94 0.85-1.05 0.93-1.38

CV 8.29 6.98 6.27 184.15 6.42 9.01

NA: Not applicable

WHO/BS/2014.2244

Table 4: dRVVT Screen ratios, confirm ratios, normalised ratios, % correction of ratio and mix and screen ratios calculated relative to local pooled normal plasma (PNP)

or relative to sample A for sample B

Against Laboratory PNP Against Sample A Screen/

confirm

ratio Lab

Screen

ratio

Confirm

ratio NR

% correction

of ratio

Mix/

Screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/

Screen

ratio

1 1.64 0.93 1.77 43.37 NA 1.76 1.06 1.66 39.82 NA 1.70

2 1.35 0.97 1.39 51.20 NA 1.44 1.04 1.39 72.22 NA 1.42

3 1.40 0.99 1.43 29.65 NA 1.41 1.05 1.34 25.42 NA 1.44

4 NA NA NA NA NA NA NA NA NA NA NA

5 1.49 1.07 1.39 27.86 NA 1.47 1.03 1.42 29.53 NA 1.48

6 1.82 1.01 1.81 44.77 NA 1.76 1.05 1.68 40.50 NA 1.92

7 1.31 0.90 1.45 30.88 1.05 1.43 1.06 1.34 25.53 NA 1.40

8a 1.46 0.98 1.48 32.49 NA 1.50 1.03 1.45 31.27 NA 1.55

8b 1.56 1.00 1.56 35.99 NA 1.56 1.02 1.53 34.63 NA 1.45

8c 1.59 1.02 1.55 35.60 NA 1.58 1.04 1.52 34.13 NA 1.65

9 1.47 1.11 1.33 24.58 1.28 1.40 1.06 1.33 24.70 1.22 1.41

10 1.67 1.01 1.65 39.54 1.34 1.71 1.04 1.65 39.23 1.38 1.81

11 1.63 1.08 1.51 33.88 1.31 1.49 1.05 1.43 29.91 1.20 1.56

12 1.93 1.14 1.69 40.77 NA 1.50 1.05 1.43 30.23 NA 1.98

13 1.45 NA NA NA 1.24 1.48 NA NA NA 1.26 1.51

14 1.40 1.04 1.34 25.52 1.21 1.38 1.03 1.34 25.34 1.19 1.45

15 1.35 0.95 1.43 30.13 NA 1.48 1.05 1.41 29.13 NA 1.37

16 1.50 1.03 1.47 31.77 0.81 1.61 1.05 1.54 34.93 NA 1.69

17 1.42 0.87 1.64 38.27 NA 1.41 1.05 1.35 25.78 NA 1.64

18a 1.36 1.12 1.22 17.77 1.13 1.27 1.09 1.17 14.35 NA 1.10

18b 1.40 0.98 1.43 30.15 1.25 1.55 1.04 1.50 33.38 NA 1.58

19 1.40 1.03 1.36 26.20 NA 1.38 NA NA NA NA 1.34

Mean 1.51 1.01 1.49 33.52 1.18 1.50 1.05 1.45 32.63 1.25 1.54

Range 1.31-1.93 0.87-1.14 1.22-1.81 17.77-51.20 0.81-1.34 1.27-1.76 1.02-1.09 1.17-1.68 24.70-72.22 1.19-1.38 1.10-1.98

CV 10.70 6.92 10.30 23.56 13.89 8.42 1.48 8.98 35.19 6.17 13.17

NA: Not applicable

WHO/BS/2014.2244


or relative to sample A for sample C


confirm

ratio Lab

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/

Screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/

Screen

ratio

1 2.17 NA NA NA NA 2.32 NA NA NA NA NA

2 1.66 1.02 1.63 82.58 NA 1.77 1.08 1.64 115.85 NA 1.67

3 1.71 1.06 1.64 38.59 NA 1.73 1.13 1.54 34.90 NA 1.66


5 1.83 1.11 1.65 39.47 NA 1.80 1.07 1.69 40.87 NA 1.76

6 2.24 1.08 2.08 51.89 NA 2.16 1.12 1.93 48.18 NA 2.20

7 1.60 0.99 1.62 38.17 1.22 1.75 1.16 1.50 33.40 1.34 1.56

8a 1.84 1.04 1.77 43.47 NA 1.89 1.09 1.74 42.45 NA 1.85

8b 1.98 1.07 1.85 46.02 NA 1.98 1.09 1.81 44.87 NA 1.72

8c 1.99 1.09 1.82 45.12 NA 1.97 1.11 1.78 43.87 NA 1.93

9 1.67 1.16 1.44 30.48 1.44 1.60 1.11 1.44 30.61 1.38 1.53

10 2.08 1.06 1.95 48.73 1.64 2.12 1.09 1.94 48.47 1.69 2.13

11 2.07 1.15 1.79 44.26 1.59 1.90 1.12 1.69 40.92 1.46 1.85

12 2.31 1.20 1.92 47.88 NA 1.80 1.10 1.63 38.62 NA 2.25

13 1.77 NA NA NA 1.46 1.81 NA NA NA 1.49 1.77

14 1.73 1.09 1.58 36.71 1.45 1.69 1.07 1.58 36.56 1.42 1.70

15 1.71 1.00 1.71 41.53 NA 1.87 1.11 1.69 40.69 NA 1.64

16 1.90 1.08 1.76 43.13 0.78 2.03 1.10 1.84 45.76 1.59 2.02

17 1.75 0.94 1.87 45.98 NA 1.74 1.13 1.54 35.03 NA 1.87

18a 1.51 1.21 1.25 19.18 1.05 1.41 1.18 1.19 15.86 1.22 1.13

18b 1.77 1.03 1.72 41.81 1.54 1.97 1.09 1.80 44.50 1.70 1.90

19 1.72 1.06 1.63 38.47 NA 1.69 NA NA NA NA 1.60

Mean 1.86 1.08 1.72 43.34 1.35 1.86 1.11 1.67 43.41 1.48 1.79

Range 1.51-2.31 0.94-1.21 1.25-2.08 19.18-82.58 0.78-1.64 1.41-2.32 1.07-.18 1.19-1.94 15.86-115.85 1.22-1.70 1.13-2.25

CV 11.68 6.53 10.99 27.55 20.83 10.98 2.63 11.11 45.25 10.99 14.44

NA: Not applicable

WHO/BS/2014.2244


or relative to sample A for sample Z


confirm

ratio Lab

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/

Screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/

Screen

ratio

1 1.29 0.99 1.31 23.85 NA 1.38 1.12 1.24 19.07 NA 1.26

2 1.24 0.97 1.28 37.62 NA 1.32 1.04 1.28 54.17 NA 1.31

3 1.46 0.93 1.57 36.08 NA 1.47 1.00 1.47 32.19 NA 1.59


5 1.37 1.06 1.30 23.07 NA 1.35 1.02 1.33 24.86 NA 1.39

6 1.51 0.95 1.59 37.07 NA 1.46 0.99 1.48 32.20 NA 1.68

7 1.16 0.86 1.35 25.83 1.03 1.27 1.01 1.25 20.10 1.13 1.30

8a 1.39 0.97 1.43 30.03 NA 1.43 1.02 1.40 28.76 NA 1.50

8b 1.45 1.00 1.46 31.45 NA 1.45 1.01 1.43 29.99 NA 1.35

8c 1.47 1.00 1.47 32.03 NA 1.46 1.02 1.44 30.49 NA 1.56

9 1.28 1.11 1.15 13.35 1.14 1.23 1.06 1.16 13.51 1.09 1.23

10 1.42 0.98 1.45 30.74 1.20 1.46 1.01 1.44 30.39 1.23 1.58

11 1.57 1.02 1.53 34.84 1.23 1.44 1.00 1.45 30.93 1.13 1.58

12 1.79 1.17 1.52 34.41 NA 1.39 1.07 1.29 22.72 NA 1.79

13 1.30 NA NA NA 1.14 1.33 NA NA NA 1.17 1.35

14 1.35 1.00 1.35 25.79 1.17 1.32 0.98 1.34 25.61 1.15 1.45

15 1.10 0.95 1.16 13.72 NA 1.21 1.06 1.14 12.47 NA 1.11

16 1.23 1.04 1.18 15.39 0.91 1.31 1.06 1.24 19.31 1.20 1.36

17 1.40 0.84 1.70 39.41 NA 1.40 1.01 1.39 27.53 NA 1.70

18a 1.24 1.09 1.14 11.46 0.85 1.15 1.06 1.09 7.82 1.05 1.02

18b 1.29 0.94 1.38 27.70 1.14 1.44 0.99 1.45 31.05 1.27 1.53

19 1.27 1.00 1.26 20.52 NA 1.24 NA NA NA NA 1.25

Mean 1.36 0.99 1.38 27.22 1.09 1.36 1.03 1.33 25.96 1.16 1.42

Range 1.10-1.79 0.93-1.17 1.14-1.70 11.46-39.41 0.85-1.23 1.15-1.47 0.98-1.12 1.09-1.48 7.82-54.17 1.05-1.27 1.02-1.79

CV 11.27 7.85 11.56 32.03 12.05 7.06 3.49 9.10 38.47 5.89 13.93

NA: Not applicable

WHO/BS/2014.2244

Table 7: %CV for screen, confirm and normalised ratios for sample A


Screen ratio Confirm ratio NR

Lab Mean %CV Mean %CV Mean %CV

1 0.94 0.84 0.88 1.37 1.06 0.58

2 0.94 0.01 0.94 0.01 1.00 0.01

3 0.99 6.45 0.93 10.98 1.06 5.38

4 NA NA NA NA NA NA

5 1.02 1.61 1.04 1.72 0.98 2.93

6 1.04 0.74 0.96 1.44 1.08 2.10

7 0.91 3.47 0.85 1.80 1.08 2.01

8a 1.97 1.11 0.96 0.52 1.02 1.17

8b 1.00 0.27 0.98 0.52 1.02 0.74

8c 1.01 0.82 0.98 1.43 1.02 0.71

9 1.05 0.97 1.05 1.78 1.00 1.65

10 0.98 3.39 0.97 1.24 1.01 2.15

11 1.09 1.14 1.03 1.57 1.06 0.46

12 1.29 1.48 1.09 0.23 1.18 1.26

13 0.98 1.07 NA NA NA NA

14 1.02 0.64 1.02 0.31 1.00 0.43

15 0.91 1.71 0.90 1.52 1.01 0.19

16 0.93 3.16 0.98 2.73 0.95 0.71

17 1.00 3.90 0.83 11.85 1.21 11.79

18a 1.07 5.91 1.03 0.93 1.05 6.77

18b 0.90 1.66 0.95 1.39 0.95 0.51

19 1.02 5.24 1.02* NA 1.03* NA

Range 0.90-1.29 0.01-6.45 0.83-1.09 0.01-11.85 0.95-1.21 0.01-11.79

*Result from one day only; NA: Not applicable

WHO/BS/2014.2244

Table 8: %CV for screen, confirm and normalised ratios for sample B



1 1.64 1.06 0.93 0.73 1.77 0.36

2 1.35 0.002 0.97 0.01 1.39 0.01

3 1.40 6.66 0.99 12.58 1.43 7.91

4 NA NA NA NA NA NA

5 1.49 1.92 1.07 0.74 1.39 1.72

6 1.82 1.23 1.01 1.41 1.81 2.46

7 1.31 2.85 0.90 0.89 1.45 1.96

8a 1.46 0.81 0.98 0.73 1.48 0.21

8b 1.56 1.10 1.00 2.00 1.56 1.33

8c 1.59 1.03 1.02 0.60 1.55 0.43

9 1.47 1.92 1.11 0.68 1.33 2.27

10 1.67 4.02 1.01 1.19 1.65 2.84

11 1.63 0.53 1.08 0.67 1.51 0.93

12 1.93 0.70 1.14 1.23 1.69 1.80

13 1.45 1.73 NA NA NA NA

14 1.40 2.58 1.05 0.99 1.34 3.58

15 1.35 0.94 0.95 1.16 1.43 1.00

16 1.50 4.45 1.03 3.88 1.47 3.08

17 1.42 6.31 0.87 11.68 1.64 13.88

18a 1.36 8.61 1.12 0.64 1.22 9.14

18b 1.40 1.38 0.98 1.72 1.43 0.97

19 1.40 0.91 1.03 0.99 1.36 1.75

Range 1.31-1.93 0.002-8.61 0.90-1.14 0.01-12.58 1.22-1.81 0.01-9.14

NA: Not applicable

WHO/BS/2014.2244

Table 9: %CV for screen, confirm and normalised ratios for sample C



1 2.17 2.21 NA NA NA NA

2 1.66 0.003 1.02 0.02 1.63 0.02

3 1.71 5.91 1.06 13.42 1.64 8.45

4 NA NA NA NA NA NA

5 1.83 2.06 1.11 1.00 1.65 2.52

6 2.24 1.52 1.08 1.58 2.08 2.64

7 1.60 5.06 0.99 1.61 1.62 3.70

8a 1.84 1.54 1.04 0.82 1.77 0.90

8b 1.98 1.26 1.07 1.21 1.85 0.06

8c 1.99 1.07 1.09 0.40 1.82 1.40

9 1.67 1.79 1.16 1.30 1.44 2.52

10 2.08 4.17 1.06 1.21 1.95 3.54

11 2.07 1.59 1.15 1.35 1.79 2.13

12 2.31 1.45 1.20 1.45 1.92 1.85

13 1.77 1.55 NA NA NA NA

14 1.73 2.77 1.09 1.24 1.58 3.37

15 1.71 0.50 1.00 0.88 1.71 0.62

16 1.90 3.27 1.08 2.16 1.76 1.24

17 1.75 5.39 0.94 13.54 1.87 13.74

18a 1.51 11.05 1.21 0.95 1.25 11.41

18b 1.77 1.73 1.03 1.50 1.72 0.72

19 1.72 0.91 1.06 0.20 1.63 0.75

Range 1.51-2.24 0.003-

11.05 0.94-1.20 0.02-13.54 1.25-2.08 0.02-11.41

NA: Not applicable

WHO/BS/2014.2244

Table 10: %CV for screen, confirm and normalised ratios for sample Z



1 1.29 1.41 0.99 0.80 1.31 1.46

2 1.24 0.0003 0.97 0.01 1.28 0.01

3 1.46 7.52 1.03 12.95 1.57 5.95

4 NA NA NA NA NA NA

5 1.37 1.56 1.06 0.49 1.30 1.99

6 1.51 1.04 0.95 1.25 1.59 0.50

7 1.16 3.85 0.86 1.50 1.35 2.36

8a 1.39 1.81 0.97 1.77 1.43 2.00

8b 1.45 1.16 1.00 0.50 1.46 1.49

8c 1.47 2.56 1.00 0.16 1.47 2.71

9 1.28 2.26 1.11 0.90 1.15 2.39

10 1.42 3.04 0.98 2.88 1.45 4.81

11 1.57 0.36 1.03 0.57 1.53 0.89

12 1.79 1.00 1.17 2.62 1.52 1.86

13 1.30 0.92 NA NA NA NA

14 1.35 1.72 1.00 0.64 1.35 1.30

15 1.10 0.54 0.95 0.70 1.16 0.44

16 1.23 1.78 1.04 1.93 1.18 0.38

17 1.40 11.12 0.84 9.40 1.70 21.53

18a 1.24 8.44 1.09 1.34 1.14 9.74

18b 1.29 4.30 0.94 1.68 1.38 2.70

19 1.27 2.38 1.00* 1.59* 1.26* 6.73*

Range 1.10-1.79 0.0003-

11.12 0.84-1.17 0.01-12.95 1.14-1.59 0.01-21.53

*Results from 2 days only; NA: Not applicable

WHO/BS/2014.2244

Table 11: Comparison of dRVVT ratios against local pooled normal plasma (PNP) and Sample A: Mean and inter-laboratory %CV with p values

obtained by two tailed paired t-test

Sample B

Screen ratio Confirm ratio NR % correction of ratio Mix/Screen

Vs PNP Vs A Vs PNP Vs A Vs PNP Vs A Vs PNP Vs A Vs PNP Vs A

mean 1.51 1.50 1.01 1.05 1.49 1.45 33.52 32.63 1.18 1.25

range 1.31-1.93 1.27-1.76 0.87-1.14 1.02-1.09 1.22-1.81 1.17-1.68 17.77-

51.20

24.70-

72.22 0.81-1.34 1.19-1.38

%CV 10.70 8.42 6.92 1.48 10.30 8.98 23.56 35.19 13.89 6.17

Sample C



mean 1.86 1.86 1.08 1.11 1.72 1.67 43.34 43.41 1.35 1.49

range 1.51-2.31 1.41-2.32 0.94-1.21 1.07-1.18 1.25-2.08 1.19-1.94 19.18-

82.58

15.86-

115.85 0.78-1.64 1.22-1.70

%CV 11.68 10.98 6.53 2.63 10.99 11.11 27.55 45.25 20.83 8.06

Sample Z



mean 1.36 1.36 0.99 1.03 1.38 1.33 27.22 25.96 1.09 1.15

Range 1.10-1.79 1.15-1.47 0.93-1.17 0.98-1.12 1.14-1.70 1.09-1.48 11.46-

39.41 7.82-54.17 0.85-1.23 1.05-1.27

%CV 11.27 7.06 7.85 3.49 11.56 9.10 32.03 38.47 12.05 4.45

WHO/BS/2014.2244

APTT APTT is recommended by the BCSH guidelines as a screening test, with mixing tests

recommended if APTT clotting time is prolonged. If the samples were clotting factor deficient

rather than positive for lupus anticoagulant, mixing with normal pooled plasma should correct

the prolonged clotting time. The revised ISTH guidelines also recommend a sensitive APTT

(low phospholipids and silica as activator) as one of the two tests that should be carried out, the

first choice being dRVVT. Sixteen sets of data were analysed for screen ratios. Ten laboratories

returned results for mixing studies, with 2 labs returning data for mixing studies only. Table 8

shows the individual laboratories’ mean screen ratio and mix ratio for sample A. The overall

laboratories’ mean screen ratio was found to be 1.08 (range 0.95 – 1.19) indicating that sample A

is lupus negative. Tables 9, 10 and 11 give summary of individual laboratory APTT results for

samples B, C and Z relative to PNP and sample A (where possible). The overall mean screen

ratios for samples B, C and Z are 1.40 (range 1.01 – 1.92), 1.68 (range 1.07 – 2.52) and 1.27

(range 1.06 – 1.56) respectively. For samples B and C, the prolongation of clotting times were

not corrected in the mixing studies confirming that these samples are lupus positive rather than

factor deficient. For sample Z, the mixing studies results suggest correction of some of the

screen clotting times, however, this could be due to the “over” dilution of a very weak lupus

anticoagulant. With the exception of Labs 8a2, 8b2, 8c2 and 15a who obtained screen ratio

results that suggest sample B was weaker than sample Z, the individual laboratory mean and

overall mean screen ratio showed the same order of lupus positivity as those found with dRVVT:

C>B>Z. The differences in the order of positivity were probably due to the APTT reagents used

since 8a1, 8b1, 8c1 obtained the correct order of lupus positivity and they have used the same

instruments as Lab 8a2, 8b2, 8c2. The intra-laboratory variation for APTT was similar to that

found for dRVVT, with %CV ranges of 0.08-5.70, 0.18-9.96, 0.02-5.75, 0.02-5.75 for samples A,

B, C, Z, respectively (see Appendix 3).

The screen and mix ratios relative to sample A are also shown in Tables 9, 10 and 11 and a

summary of comparison of ratios against PNP and sample A, together with inter-

laboratory %CV is given in Table 12. In general, both screen and mix ratios were lower relative

to sample A than against local PNP. With the exception of screen ratio for Sample C, the

agreement between laboratories was improved when the ratios were calculated relative to sample

A.

Table 8: Summary of laboratory APTT results for sample A


Lab Screen ratio Mix/Screen ratio

1 1.12 1.02

5 1.04 1.04

6 1.16 NA

7 1.19 1.09

8a1 1.09 NA

8a2 1.09 NA

8b1 1.12 NA

8b2 1.11 NA

8c1 1.12 NA

8c2 1.11 NA

9 1.03 1.00

10 0.97 0.89

11a 1.16 1.06

WHO/BS/2014.2244

15a 0.95 NA

15b 1.02 NA

18 1.00 0.97

19a NA 1.07

19b NA 1.08

Mean 1.08 1.02

Range 0.95-1.19 0.89-1.09

%CV 6.53 6.44

NA: Not applicable

Table 9: Summary of laboratory APTT results for sample B

Against Laboratory PNP Against Sample A

Lab Screen ratio Mix/Screen ratio Screen ratio Mix/Screen ratio

1 1.92 1.55 1.71 1.39

5 1.46 1.10 1.40 1.06

6 1.63 1.71 1.41 1.46

7 1.64 1.30 1.38 1.09

8a1 1.36 NA 1.24 NA

8a2 1.21 NA 1.12 NA

8b1 1.33 NA 1.19 NA

8b2 1.24 NA 1.11 NA

8c1 1.35 NA 1.20 NA

8c2 1.24 NA 1.11 NA

9 1.56 1.11 1.51 1.08

10 1.26 1.25 1.30 1.29

11a 1.68 1.47 1.46 1.27

15 a 1.01 NA 1.07 NA

15b 1.25 NA 1.22 NA

18 1.20 1.09 1.20 1.09

19a NA 1.10 NA NA

19b NA 1.49 NA NA

Mean 1.40 1.30 1.29 1.22

Range 1.01-1.92 1.09-1.71 1.07-1.71 1.06-1.39

%CV 16.70 17.72 13.66 13.10

NA: Not applicable

WHO/BS/2014.2244

Table 10: Summary of laboratory APTT results for sample C



1 2.52 1.72 2.26 1.54

5 1.70 1.32 1.63 1.27

6 2.10 1.71 1.81 1.46

7 2.16 1.54 1.81 1.29

8a1 1.62 NA 1.49 NA

8a2 1.33 NA 1.22 NA

8b1 1.51 NA 1.35 NA

8b2 1.37 NA 1.23 NA

8c1 1.55 NA 1.37 NA

8c2 1.38 NA 1.24 NA

9 1.89 1.55 1.83 1.49

10 1.58 1.24 1.63 1.28

11a 2.10 1.61 1.81 1.40

15 a 1.07 NA 1.13 NA

15b 1.55 NA 1.52 NA

18 1.40 1.20 1.40 1.20

19a NA 1.12 NA NA

19b NA 1.63 NA NA

Mean 1.68 1.44 1.55 1.37

Range 1.07-2.52 1.12-1.72 1.13-2.26 1.20-1.54

%CV 22.65 15.78 19.58 9.04

NA: Not applicable

WHO/BS/2014.2244

Table 11: Summary of laboratory APTT results for sample Z



1 1.33 1.08 1.19 0.96

5 1.25 1.02 1.20 0.98

6 1.56 1.31 1.35 1.12

7 1.28 1.14 1.08 0.95

8a1 1.22 NA 1.12 NA

8a2 1.28 NA 1.18 NA

8b1 1.19 NA 1.07 NA

8b2 1.34 NA 1.21 NA

8c1 1.21 NA 1.08 NA

8c2 1.35 NA 1.21 NA

9 1.23 1.07 1.19 1.03

10 1.20 1.01 1.24 1.04

11a 1.48 1.23 1.28 1.07

15 a 1.06 NA 1.12 NA

15b 1.24 NA 1.21 NA

18 1.12 1.07 1.12 1.07

19a NA 1.11 NA NA

19b NA 1.24 NA NA

Mean 1.27 1.11 1.18 1.03

Range 1.06-1.56 1.01-1.31 1.08-1.35 0.95-1.12

%CV 9.64 8.97 6.54 5.70

NA: Not applicable

WHO/BS/2014.2244

Table 2: Comparison of APTT ratios against local pooled normal plasma (PNP) and Sample A:

Mean and inter-laboratory %CV test

Sample B

Screen ratio Confirm ratio

Vs PNP Vs A Vs PNP Vs A

mean 1.40 1.29 1.30 1.22

range 1.01-1.92 1.07-1.71 1.09-1.71 1.06-1.39

%CV 16.70 13.66 17.72 13.10

Sample C



mean 1.68 1.55 1.44 1.55

range 1.07-2.52 1.13-2.26 1.12-1.72 1.13-2.26

%CV 22.65 19.58 15.78 19.58

Sample Z



mean 1.27 1.18 1.11 1.03

range 1.06-1.56 1.08-1.35 1.01-1.31 0.95-1.12

%CV 9.64 6.54 8.97 5.70

SCT Four sets of data were analysed for SCT. Tables 13, 14, 15 and 16 show SCT results for samples

A, B, C and Z. The screen and normalised ratio indicated that sample A is lupus negative with

mean screen ratio of 0.97 (range 0.89 – 1.03) and mean normalised ratio of 0.93 (range 0.89 -

0.98). The screen, confirm and normalised ratios for samples B, C and Z relative to PNP

indicate these samples are all lupus positive with mean screen ratio of 1.82 (range 1.58 – 2.03),

2.31 (range 2.02 – 2.59) and 1.57 (range 1.45 – 1.70) for samples B, C and Z respectively.

The >30% correction of ratio and that incomplete neutralisation of activity in mixing study also

support the lupus positivity identity of these materials. Overall, when the ratios were calculated

relative to sample A, the inter-laboratory agreement as expressed by %CV was improved. The

ranking order of positivity was the same as those found for dRVVT and APTT: C>B>Z.

WHO/BS/2014.2244

Table 13: SCT results for sample A


Screen/

Confirm ratio Lab Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix ratio

2 0.89 0.91 0.98 -1.79 NA 0.95

5 1.03 1.16 0.89 -12.35 NA 0.85

13 1.00 NA NA NA NA NA

14 0.94 1.01 0.92 -8.21 0.95 0.89

Mean 0.97 1.03 0.93 -10.27 0.95 0.90

Range 0.89-1.03 0.91-1.16 0.89-0.98 -8.21-12.35 NA 0.85-0.95

%CV 6.49 12.22 5.04 -20.18 NA 5.76

NA: not applicable

WHO/BS/2014.2244

Table 14: SCT results for sample B


Confirm

ratio Lab

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

% correction

of ratio

Mix

ratio

2 1.58 0.93 1.71 41.32 NA 1.80 1.05 1.72 41.92 NA 1.60

5 2.03 1.23 1.66 39.54 NA 1.97 1.06 1.86 46.19 NA 1.58

13 1.95 NA NA NA 1.52 1.95 NA NA NA 1.52 1.90

14 1.70 1.06 1.61 37.81 1.52 1.82 1.04 1.74 42.53 1.62 1.55

Mean 1.82 1.07 1.66 39.56 1.52 1.52 1.05 1.77 43.55 1.57 1.66

Range 1.58-2.03 0.93-1.23 1.6-1.71 37.81-41.32 NA 1.80-1.97 1.04-1.06 1.74-1.86 41.92-46.19 NA 1.55-1.90

%CV 11.56 14.01 3.01 4.44 NA 4.64 0.83 4.19 5.31 NA 9.69

NA: not applicable

Table 15: SCT results for sample C


Screen/Confir

m ratio Lab Screen

ratio

Confirm

ratio NR

% correction

of ratio Mix ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix ratio

2 2.02 1.00 2.02 50.54 NA 2.30 1.12 2.04 51.05 NA 1.90

5 2.59 1.29 2.01 50.30 NA 2.51 1.11 2.26 55.78 NA 1.93

13 2.43 NA NA NA 1.81 2.42 NA NA NA 1.81 2.21

14 2.20 1.15 1.92 47.41 1.84 2.35 1.14 2.07 51.43 1.97 1.84

Mean 2.31 1.15 1.98 49.42 1.83 2.40 1.12 2.13 52.75 1.89 1.97

Range 2.02-

2.59

1.00-

1.29 1.92-2.02 47.41-50.54 NA

2.30-

2.51

1.11-

1.14

2.04-

2.26 51.05-55.78 NA 1.84-2.21

%CV 10.88 12.58 3.02 3.52 NA 3.90 1.21 5.61 4.98 NA 8.31

NA: not applicable

WHO/BS/2014.2244

Table 16: SCT results for sample Z


Confirm

ratio Lab

Screen

ratio

Confirm

ratio NR

% correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

% correction

of ratio Mix ratio

2 1.45 0.96 1.50 33.41 NA 1.65 1.09 1.52 34.08 NA 1.41

5 1.70 1.24 1.37 26.78 NA 1.65 1.07 1.53 34.84 NA 1.31

13 1.64 NA NA NA 1.23 1.64 NA NA NA 1.23 1.59

14 1.49 1.08 1.39 27.84 1.23 1.59 1.06 1.50 33.32 1.32 1.33

Mean 1.57 1.09 1.42 44.23 1.23 1.63 1.07 1.52 55.63 1.27 1.41

Range 1.45-1.70 0.96-1.24 1.37-1.50 26.78-78.06 NA 1.59-1.65 1.06-1.09 1.5-1.53 33.32-98.75 NA 1.31-1.59

%CV 7.59 12.80 5.21 66.26 NA 1.60 1.11 1.16 67.12 NA 8.94

NA: not applicable

WHO/BS/2014.2244

dPT Two laboratories carried out dPT and the results for samples A, B, C and Z relative to PNP or

sample A are shown in Tables 17, 18, 19 and 20 respectively. Although inter-laboratory

variation cannot be assessed, the ratios calculated for each laboratory were in close agreement

and indicate sample A is lupus negative with mean screen ratio of 0.98, sample B and C are

lupus positive with respective mean screen ratios of 1.24 and 1.70. However, the mean screen

ratio for sample Z was 0.97 indicating that the weak Lupus Anticoagulant in sample Z is not

detected by dPT. The ranking order of positivity was C>B>Z.

Table 17: dPT results for sample A relative to PNP


Screen/Confirm

ratio Lab Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

16 1.01 0.97 1.04 3.52 0.97 0.94

18 0.96 0.88 1.11 7.88 NA 0.94

Mean 0.98 0.93 1.07 5.70 NA 0.94

NA: not applicable

WHO/BS/2014.2244

Table 18: dPT results for sample B relative to PNP or sample A


Screen/Confirm

ratio Lab Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

16 1.26 1.10 1.15 12.99 0.85 1.25 1.13 1.11 9.86 NA 1.05

18 1.22 1.07 1.16 11.38 1.04 1.27 1.22 1.04 4.05 1.08 0.98

Mean 1.24 1.09 1.15 12.18 0.94 1.26 1.17 1.08 6.96 NA 1.02

Table 19: dPT results for sample C relative to PNP or sample A


Screen/Confirm

ratio Lab Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

16 1.74 1.20 1.44 30.10 0.72 1.72 1.24 1.39 27.64 NA 1.31

18 1.66 1.19 1.42 28.22 1.15 1.73 1.35 1.28 22.03 1.20 1.21

Mean 1.70 1.20 1.43 29.16 0.93 1.72 1.29 1.33 24.84 NA 1.26

Table 20: dPT results for sample Z relative to PNP or sample A


Screen/Confirm

ratio Lab Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/Screen

ratio

16 1.02 0.96 1.06 5.24 0.97 1.01 0.99 1.02 1.79 NA 0.96

18 0.93 0.82 1.16 11.94 NA 0.97 0.93 1.05 4.40 NA 0.99

Mean 0.97 0.89 1.11 8.59 NA 0.99 0.96 1.03 3.09 NA 0.97

NA: not applicable

WHO/BS/2014.2244

KCT, ASLA, TSVT Only one set of data was submitted for KCT, ASLA and TSVT and the summaries of calculated

ratios are shown in Tables 21, 22 and 23 for KCT, ASLA and TSVT respectively. Both NIBSC

and local calculated ratios from all three test methods found sample A to be lupus negative,

while samples B and C were lupus positive. KCT and ASLA found sample Z lupus positive,

while it was negative/ borderline by TSVT.

aCL Lab 10 returned ELISA results for anticardiolipin antibodies measurement. As shown in Table

24, Sample A was found to contain low concentrations of both IgG and IgM, while substantially

higher concentrations of IgG were detected in samples B, C and Z. Interestingly, lower amount

of IgM by comparison with IgG were found in these samples. The IgG results confirm that

samples B, C and Z contain anticardiolipin antibodies and fit well with ranking order of these

samples by clot-based assays.

WHO/BS/2014.2244

Table 21: Summary of calculated ratios for KCT

Sample


Screen

Ratio

Intra-

lab %

CV

Mix

Ratio

Intra-

lab %

CV

Rosner

Ratio

Intra-

lab %

CV

Screen

Ratio

Intra-

lab %

CV

Mix

Ratio

Intra-

lab %

CV

Roser

Ratio

Intra-

lab %

CV

A 1.11 1.92 1.00 1.66 0.00 627.67 NA NA NA NA NA NA

B 2.27 1.02 1.81 0.28 0.36 0.73 2.05 2.89 1.82 1.80 0.31 2.68

C 2.85 1.37 2.28 1.35 0.45 3.60 2.58 2.75 2.29 0.58 0.41 1.98

Z 2.03 1.10 1.53 1.37 0.27 2.63 1.84 1.31 1.54 0.58 0.21 2.60

Local

positive 4.31 5.62 2.95 1.33 0.46 5.20 3.90 5.91 2.97 2.64 0.43 5.39

Rosner Ratio= (KCT-mix - KCT-PNP) / KCT-sample. Cutoff is 0.16

NA: Not applicable

WHO/BS/2014.2244

Table 22: Summary of calculated ratios for ASLA. Intra-laboratory variation is expressed as %CV


Sample

Screen

ratio

(%CV)

Confirm

ratio

(%CV)

NR

(%CV)

%

correction

of ratio

(%CV)

Mix ratio

(%CV)

Screen

ratio

(%CV)

Confirm

ratio

(%CV)

NR

(%CV)

%

correction

of ratio

(%CV)

Mix ratio

(%CV)

Screen/

confirm

ratio

(%CV)

A 1.24

(5.00)

1.18

(8.27)

1.06

(6.85)

5.22

(119.81) 1.08 NA NA NA NA NA

2.62

(6.55)

B 1.97

(6.79)

1.35

(3.86)

1.46

(6.29)

31.44

(13.38) 1.31

1.59

(4.93)

1.15

(5.71)

1.38

(1.25)

27.64

(3.25) 1.11

3.62

(6.84)

C 2.21

(6.04)

1.46

(7.78)

1.52

(10.20)

33.72

(19.23) 1.61

1.78

(2.88)

1.24

(1.26)

1.43

(3.53)

30.16

(8.19) 1.36

3.76

(9.95)

Z 1.67

(4.66)

1.37

(9.45)

1.22

(13.14)

17.39

(58.94) 1.30

1.34

(3.34)

1.17

(4.39)

1.15

(6.24)

13.06

(40.90) 1.10

3.03

(12.46)

Local

positive

1.66

(11.01)

1.22

(5.28)

1.36

(9.81)

26.05

(27.39) ND

1.34

(11.81)

1.04

(9.00)

1.28

(5.01)

22.04

(18.22) ND

3.37

(7.01)

ND: not done; NA: Not applicable

WHO/BS/2014.2244

Table 23: TSVT, Ratio plus intra-laboratory variation expressed as %CV


Sample Screen ratio

(%CV)

Confirm

ratio

(%CV)

NR

(%CV)

%

correction

of ratio

(%CV)

Screen ratio

(%CV)

Confirm

ratio

(%CV)

NR (%CV)

%

correction

of ratio

(%CV)

Screen/

confirm

ratio

(%CV)

A 1.05

(5.62) 1.09 0.91 -9.3 NA NA NA NA 1.31

B 1.26

(2.04)

1.08

(2.47)

1.17

(2.30)

14.17

(14.10)

1.20

(3.62) 1.00 1.24 19.36

1.54

(4.58)

C 1.33

(2.99)

1.14

(1.63)

1.16

(4.07)

14.00

(25.33)

1.27

(2.69) 1.06 1.22 17.73

1.54

(3.03)

Z 1.14

(4.30) 1.06 1.04 3.62

1.09

(1.30) 0.97 1.13 11.81 1.48

Local

positive

1.43

(6.98)

0.95

(5.82)

1.51

(6.49)

33.40

(13.20)

1.37

(9.23) 0.81 1.66 39.70

1.99

(10.03)

NA: not applicable

WHO/BS/2014.2244

Table 24: Anticardiolipin antibody results

Sample

aCL IgG

(GPL/mL)

aCL IgM

(MPL/mL)

mean %CV mean %CV

Local

negative 0.00 NA 0.00 NA

A 2.33 12.37 4.00 43.30

B 42.83 20.03 5.17 47.74

C 63.33 22.50 6.17 32.77

Z 26.00 13.32 19.83 18.24

Local

positive 45.00 2.22 50.00 2.00

NA: not applicable

Stability studies Accelerated degradation studies of 12/148, 12/150 and 12/152 have been initiated. Lupus

anticoagulant tests cannot be used to assess stability as a quantitative measurement is not

possible, therefore coagulation factors V, VII and VIII activity are used as stability indicators.

The first time-point (4.5 months storage) was assessed for loss of potency of FV and FVII to

indicate the stability of the plasma. The second time-point (1 year) was assessed for loss of

potency of FV, FVII and FVIII. The results shown below are cumulative for both time-points

for FV and FVII. The stability studies are on-going but data after 1 year indicate that the

materials are stable, with <0.2% loss per year at the storage temperature of -20°C.

12/148

Storage

temperature (°C) Predicted loss per year (%)

FV FVII FVIII

-150 0.000 0.000 0.000

-70 0.000 0.000 0.000

-20 0.002 0.000 0.175

4 0.161 0.020 1.876

20 2.173 0.630 7.190

37 23.115 15.340 23.984

12/150

Storage


FV FVII FVIII

-150 0.000 0.000 0.000

-70 0.000 0.000 0.000

-20 0.000 0.000 0.001

4 0.197 0.000 0.137

20 2.243 0.040 1.950

37 20.576 6.425 21.850

WHO/BS/2014.2244

12/152

Storage


FV FVII FVIII

-150 0.000 0.000 0.000

-70 0.000 0.000 0.000

-20 0.007 0.000 0.052

4 0.349 0.030 0.924

20 3.151 0.736 4.763

37 23.063 14.516 21.012

On-bench stability was assessed using DRVVT. Two ampoules were reconstituted at 0 h, kept

on ice, and assayed by DRVVT at 0 h, 1 h, 2 h and 3 h. A freshly reconstituted ampoule of each

material was also assayed at each time-point for comparison. The results show that the status of

the materials do not alter over a 3 hour period, with 12/148 remaining negative throughout,

12/150 and 12/152 remaining positive. The results for the screen and confirm clotting times and

the screen/confirm ratio at all time-points assess agree well with those of the freshly

reconstituted ampoules, indicating that this material is stable for at least 3 hours when kept on ice.

12/148

0 h 12/148 Fresh 12/148

Screen

(Average)

41.5, 41.0

(41.25)

40.1, 41.3

(40.7)

Confirm

(Average)

40.6, 39.4

(40)

39.0, 38.9

(38.95)

Ratio 1.03 1.05

1 h

Screen

(Average)

45.7, 45.2

(45.60)

44.0, 43.4

(43.70)

Confirm

(Average)

39.4, 39.3

(39.35)

37.9, 37.7

(37.8)

Ratio 1.16 1.16

2 h

Screen

(Average)

41.3, 41.3

(41.30)

40.4, 38.9

(39.65)

Confirm

(Average)

39.4, 39.8

(38.6)

38.3, 37.9

(38.1)

Ratio 1.07 1.04

3 h

Screen

(Average)

42.6, 42.3

(42.45)

40.8, 40.0

(40.40)

Confirm

(Average)

38.8, 38.7

(38.75)

37.5, 37.2

(37.35)

Ratio 1.10 1.08

WHO/BS/2014.2244

12/150

0 h 12/150 Fresh 12/150

Screen

(Average)

56.9, 57.1

(57.00)

56.2, 58.2

(57.20)

Confirm

(Average)

42.5, 41.3

(41.90)

44.1, 41.4

(42.75)

Ratio 1.36 1.34

1 h

Screen

(Average)

63.6, 62.6

(63.10)

58.6, -

(58.60)

Confirm

(Average)

40.3, 40.1

(40.20)

39.9, 40.7

(40.30)

Ratio 1.57 1.45

2 h

Screen

(Average)

56.9, 58.0

(57.45)

56.0, 55.8

(55.90)

Confirm

(Average)

41.1, 40.0

(40.55)

42.3, –

(42.3)

Ratio 1.42 1.32

3 h

Screen

(Average)

61.4, 59.1

(60.25)

56.0, –

(56.00)

Confirm

(Average)

40.9, 39.5

(40.20)

39.4, 39.0

(39.20)

Ratio 1.50 1.43

WHO/BS/2014.2244

12/152

0 h 12/152 Fresh 12/152

Screen

(Average)

71.8, 70.5

(71.15)

68.3, 71.1

(69.70)

Confirm

(Average)

43.0, 43.7

(43.35)

42.8, 42.9

(42.85)

Ratio 1.64 1.63

1 h

Screen

(Average)

76.7, 63.4

(70.05)

75.1, 70.7

(72.90)

Confirm

(Average)

42.7, 42.4

(42.55)

42.5, 41.5

(42.00)

Ratio 1.65 1.74

2 h

Screen

(Average)

73.2, 70.4

(71.8)

71.0, 71.6

(71.30)

Confirm

(Average)

43.2, 43.1

(43.15)

42.3, 42.9

(42.60)

Ratio 1.66 1.67

3 h

Screen

(Average)

74.1, 73.0

(73.55)

69.7, 71.1

(70.40)

Confirm

(Average)

42.2, 41.6

(41.90)

41.3, 41.4

(41.35)

Ratio 1.76 1.70

Discussion The main purpose of this study was to evaluate three lyophilised plasmas for their suitability as

reference plasmas for lupus anticoagulant detection. The intended use of this set of reference

materials is for validation of lupus anticoagulant assay methods whenever laboratories have the

need to set up new methods or change in instruments and operators or for trouble shoot. Values

will not be assigned to this panel, but information on the methods used and results obtained from

this evaluation study will be provided to the end-users.

The levels of the FII, V, VII, VIII, IX and X in the lyophilised samples are all within the normal

range (Table 1). Antithrombin, protein C and protein S were found to be greater than 0.8 IU/ml

for all 3 candidates. This shows the coagulation factors and inhibitors are well balanced and

these plasmas would be unlikely be mistaken for clotting factor deficient plasmas.

The two tests (dRVVT and APTT) recommended by the ISTH guidelines were used by the

majority of the participants and the results from these two methods, which included screening,

confirmation and mixing studies, confirmed that sample A, 12/148 is lupus negative, while

samples B (12/150) and C (12/152) were lupus positive, with sample B giving weaker responses

than sample C. Results from SCT, dPT, KCT, ASLA and TSVT also support these findings.

The in-house lupus positive control plasmas were all assessed to be lupus positive by their

respective laboratories. From the clotting times observed and ratios calculated, all in-house

positive control plasmas were strong lupus positive samples (data not shown). The intra-

laboratory variation as expressed by %CVs for all the assay methods were low, with the majority

WHO/BS/2014.2244

of CVs being less than 5%. This indicates the assay methods are well controlled in individual

laboratories and that they were able to perform these assays with good precision.

The inter-laboratory variation was reasonably low for dRVVT, but higher for SCT and APTT.

For all methods, the % inter-laboratory CVs were reduced when the ratios were recalculated

relative to sample A.

This panel is not intended as calibrants for lupus anticoagulant assay kits, and is more akin to

quality control or system suitability samples that ensure the assays can distinguish between lupus

negative and lupus positive plasma samples. Sample Z, one of the positive plasmas in the British

Lupus Anticoagulant Reference panel established in 1999 was included in this study to ascertain

the relationship of the proposed panel with a common sample that has been produced and

established from known lupus positive patient plasmas. With the exception of TSVT, this

reference plasma was found to be lupus positive by all other methods in the current study.

Sample Z gave similar intra-laboratory and inter-laboratory variability to the proposed panel

when the different ratios were calculated relative to the local PNP and recalculation relative to

sample A also reduced the within and between laboratory variation. With the exception of

results from 1 APTT reagent (Pathromtin, Labs 8a2, 8b2, 8c2) which gave results that suggest

sample B is weaker than sample Z, the ranking order of lupus positivity by all other methods was

identical with A<Z<B<C. This suggests that the proposed panel is fit for its intended use in that

the three candidate reference plasmas have the same relationship of lupus negativity and

positivity with the common patient sample in all the assay methods tested in this study.

Proposal and Recommendation The results from this study have shown that laboratories were able to detect and confirm the

candidate reference plasmas as negative, moderate and strong lupus anticoagulant samples. This

panel of three lyophilised plasmas would help laboratories to set up and verify their test systems

and contribute towards minimising the intra- and inter-laboratory variations for lupus

anticoagulant testing.

It is therefore recommended that 12/148, 12/150 and 12/152 be established as the 1st

International Reference Panel(Plasma) for Lupus Anticoagulant and each reference plasma will

be identified as follows:

Proposed 1st International Reference Panel(Plasma) for Lupus Anticoagulant, 13/172,

12/148 Lupus negative

12/150 Lupus moderate positive

12/152 Lupus strong positive

A draft Instruction For Use (IFU) is shown in Appendix 5.

Each participant was asked to review the participants report and whether they agreed with the

proposal. All participants agreed with the proposal to establish these materials as the 1st

International Reference Panel(Plasma) for Lupus Anticoagulant. The experts nominated by the

Lupus Anticoagulant/Phospholipid-Dependent Antibodies Subcommittee of the Scientific and

Standardisation Committee (SSC) of the International Society on Thrombosis and Haemostasis

have also reviewed the study. The SSC has now endorsed the proposal to go forward for

establishment by the ECBS.

WHO/BS/2014.2244

References 1. Pengo V, Tripodi A, Reber G, Rand JH, Ortel TL, Galli M, De Groot PG; Subcommittee

on Lupus Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation

Committee of the International Society on Thrombosis and Haemostasis. Update of the

guidelines for lupus anticoagulant detection. Subcommittee on Lupus

Anticoagulant/Antiphospholipid Antibody of the Scientific and Standardisation

Committee of the International Society on Thrombosis and Haemostasis. J Thromb

Haemost. 2009 Oct;7(10):1737-40.

2. Greaves M, Cohen H, MacHin SJ, Mackie I. Guidelines on the investigation and

management of the antiphospholipid syndrome. Br J Haematol. 2000 Jun;109(4):704-15.

3. Jennings I, Kitchen S, Woods TAL, Preston FE, Greaves M. Potentially Clinically

Important Inaccuracies In Testing For The Lupus Anticoagulant: An Analysis Of Results

From Three Surveys Of The Uk National External Quality Assessment Scheme (NEQAS)

For Blood Coagulation. Thrombosis and Haemostasis 1997; 77: 934-7

4. Jennings I, Greaves M, Mackie IJ, Kitchen S, Woods TAL, Preston FE. Lupus

Anticoagulant Testing: Improvements in performance in a UK NEQAS proficiency

testing exercise after dissemination of national guidelines on laboratory methods. Brit J

Haem 2002, 119; 364-9

5. Jennings I, Mackie I, Arnout J, Preston FE; UK National External Quality Assessment

Scheme for Blood Coagulation. Lupus anticoagulant testing using plasma spiked with

monoclonal antibodies: performance in the UK NEQAS proficiency testing programme.

J Thromb Haemost. 2004 Dec;2(12):2178-84.

6. Jennings I, Kitchen S, Kitchen DP, Woods TAL, Walker ID. ISTH/SSC lupus

anticoagulant testing guidelines: how far have these been adopted by laboratories? J

Thromb Haemost. 2011: 9(10):2117-2119

7. Dembitzer et al. Lupus Anticoagulant Testing, Performance and Practices by North

American Clinical Laboratories. American Journal of Clinical Pathology, 2010; 134,

764-773.

8. Moore GW, Henley A, Greenwood CK, Rangarajan S: Further evidence of false negative

screening for lupus anticoagulants. Thromb Res; 2008;121(4):477-84

Acknowledgements The authors would like to thank Ian Jennings (UK NEQAS) and Ian Mackie (University College

London) for scientific advice, Beverley Hunt and Kiran Parmar (St Thomas’ Hospital, London)

for collection of patient plasma, Peter Rigsby (NIBSC) for statistical advice, Bill Pickering

(NIBSC) and Sarah Daniels and John Hogwood (NIBSC) for coagulation factor screening assays.

This study would not have been possible without the collaboration of the participants.

WHO/BS/2014.2244

Appendix 1: List of Participants

Susan Cooper and Dr Steve Kitchen, Royal Hallamshire Hospital, Sheffield, UK

Dr Jörn Meuer, Siemens Healthcare Diagnostics, Marburg, Germany

Dr Ian Mackie, University College London, London, UK

Marc Goldford, r2 Diagnostics Inc, Indiana, USA

Dr Hugh JL Fryer, Sekisui Diagnostics, LLC, Stamford, Connecticut, USA

Mag. Harald Sevcik MSc and Dr Nikolaus Binder PhD, Technoclone GmbH, Vienna, Austria

Dr Olga Amengual and Prof. Tatsuya Atsumi Hokkaido University Graduate School of Medicine,

Sapporo, Japan

Dr Albert Huisman and Prof Dr Ph.G. De Groot, University Medical Center, Utrecht, The

Netherlands

Elisa Bison and Prof. Vittorio Pengo, Policlinico Universitario, Padova, Italy

Dr Ralph Bottenus and Dr Zhenghua Cao, Instrumentation Laboratory, Orangeburg, USA

Dr Helen Swalwell, Helena Biosciences Europe, Tyne and Wear, UK

Gail Filgate and Lisa Reid-Fifoot, Precision Biologic Inc, Nova Scotia, Canada

Dr Emmanuel J Favaloro, Institute of Clinical Pathology and Medical Research (ICPMR),

Westmead, Australia

Elaine Bromidge, Iulia Squires, Robert Archer and Dr Gary Moore, Guy's and St Thomas' NHS

Foundation Trust / GSTS Pathology, London, UK

Dr Jean Amiral and Laetitia Frank, Hyphen-BioMed SAS, Nueville sue Oise, France

Zurina Romay-Penabad and Dr Silvia Pierangeli, University of Texas Medical Branch,

Antiphospholipid Standardization Laboratory, Galveston, Texas, USA

Prof. Dr. K. Devreese, Ghent University Hospital, Gent, Belgium

Dr Helen Wilmot, NIBSC, Potters Bar, UK

Veena Chantarangkul and Prof. Armando Tripodi, Angelo Bianchi Bonomi Hemophilia and

Thrombosis Center, Milano, Italy

WHO/BS/2014.2244

Appendix 2: Methods, reagents, instrument and controls used by each participant

Lab Method Reagents & Source Instrument Negative control Positive control

1 dRVVT LA Check

LA Sure

Precision Biologic

STA-R, Stago Precision Biologic Pooled Normal

Plasma

23 donors

≤1.21

Precision Biologic

Cryocheck Lupus positive

≥1.21

1 APTT

+50:50 mix

APTT-SP

Instrumentation Laboratory

STA-R, Stago Precision Biologic Pooled Normal

Plasma

23 donors

26.1-43.1 s

In-house LA positive

>43.1 s

2 dRVVT LAC screen

LAC confirm


ACL TOP,

Instrumentation

Laboratory

Platelet poor normal (local

negative)

125 donors

Local positive

6 donors

Diluted in local negative

2 SCT SCT


ACL TOP,

Instrumentation

Laboratory

Platelet poor normal (local

negative)

125 donors

Local positive

6 donors

Diluted in local negative

3 dRVVT Technoclot screen and

confirm

Technoclone

KC4 Amelung Platelet poor plasma

Technoclone

0.79-1.31

N/A

4 APTT

80:20 mix only

PTT-LA

Stago

START4, Stago 1 donor

In-house positive control

4 dRVVT

80:20 mix only

LA Gradipore START4, Stago 1 donor

<1.3 ratio

Patient plasma

1 donor

5 dRVVT

+50:50 mix

LAC screen

LAC confirm


ACL TOP 500,

Instrumentation

Laboratory

Local pool

100 donors

0.93-1.14

Negative: HemosIL

HemosIL Positive

5 SCT

+50:50 mix

SCT


ACL TOP 500,

Instrumentation

Laboratory

Local pool

100 donors

0.98-1.26

Negative: HemosIL

HemosIL Positive

5 APTT SynthASil ACL TOP 500, Local pool HemosIL Positive

WHO/BS/2014.2244

+50:50 mix Instrumentation Laboratory Instrumentation

Laboratory

100 donors

25.9-35.0 s

Negative: HemosIL

6 dRVVT

+50:50 mix

LA screen

LA confirm

Life Diagnostics

Sysmex CS2000i Precision Biologic Cryocheck

normal pool

Screen 42.2-46.7

Confirm 40.2-42.9

Reference range for calculations:

Screen reference 0.85-1.17, Mean

46.6 s

Confirm reference 0.90-1.10,

Mean 38.3 s

Precision Biologic Weak

Control

Screen 1.72-2.06

Confirm 1.00-1.16

6 APTT

+50:50 mix

PTT-LA, Stago

Confirmatory reagent:

BIO/DATA Corporation

LA confirmation


normal pool

DAPPT 37.7-42.5

Confirm 45.9-49.1



40.5 s

Confirm reference 0.82-1.18,

Mean 46.5 s


Control

DAPPT 1.35-1.75

Confirm 1.10-1.22

6 ASLA

+50:50 mix

NovoSeven FVIIa

Bell and Alton platelet

substitute, Diagnostic

Reagents


normal pool

ASLA 45.2-55.2

Confirm 20-28



49.7 s

ASLAC reference 0.92-1.08,


Control

ASLA 1.68-1.92

ASLAC 0.94-1.10

WHO/BS/2014.2244

Mean 22.2 s

6 TSVT Taipan venom

Ecarin

Diagnostic Reagents


normal pool

TSVT 23-29

ET 19.2-22.3



27.7 s

ET reference 0.88-1.14, Mean 20.3

s

In-house positive

7 dRVVT

+50:50 mix

Screen/confirm

Helena Biosciences

CA-1500 Sysmex Speciality Assayed Control plasma

N

Helena Biosciences

Strong S plasma

Helena Biosciences

2.1-2.8

7 APTT

+50:50 mix

APTT SiL Plus

Helena Biosciences

CA-1500 Sysmex Speciality Assayed Control plasma

N

Helena Biosciences

28.7-38.8 s

Strong S plasma

Helena Biosciences

8a dRVVT LA1

LA2

Siemens

BCS XP Control plasma N, Siemens

28.7-43.1 s LA1

26.2-39.2 s LA2

LA control High, Siemens

62.8-94.2 LA1

31.9-47.9 LA2

8b dRVVT LA1

LA2

Siemens

CA-1500

Sysmex

Control plasma N, Siemens

29.7-44.5 s LA1

29.6-44.4 s LA2


63.0-94.4 s LA1

36.7-55.1 s LA2

8c dRVVT LA1

LA2

Siemens

CS-2000i

Sysmex


28.3-42.5 s LA1

46.4-39.6 s LA2


62.8-94.2 LA1

31.9-47.9 LA2

8a1 APTT Actin FSL

Siemens


23.5-31.7 s

LA control high, Siemens

8b1 APTT Actin FSL

Siemens

CA-1500

Sysmex


22.2-30.0


8c1 APTT Actin FSL CS-2000i Control plasma N, Siemens LA control high, Siemens

WHO/BS/2014.2244

Siemens Sysmex 22.2-30.0 s

8a2 APTT Pathromtin SL

Siemens


28.4-38.4 s


8b2 APTT Pathromtin SL

Siemens

CA-1500

Sysmex


28.8-39.0 s


8c2 APTT Pathromtin SL

Siemens

CS-2000i

Sysmex


28.8-39.0 s


9 dRVVT

+50:50 mix

Bell and Alton Platelet

substitute

Russell’s Viper Venom

Diagnostic Reagents

CS7000

Sysmex

Local pool

20 donors

0.94-1.22

Patient pool

100+ donors

1.38-1.61

9 APTT

+50:50 mix

+80:20 mix

Synthasil


CS2100i Local pool

20 donors

26-37 s

Patient pool

100+ donors

10 dRVVT

+50:50 mix

screen&confirm

STA clot screen & confirm

Stago

Siemens BCS STA pool normal – Stago

20+ donors

TriniCHECK positive

control

Trinity Biotech

10 APTT

+50:50 mix

Triniclot HS

Trinity Biotech

STAR Evolution

Stago

In-house pool TriniCHECK positive

control

Trinity Biotech

10 aCL In-house Best 2000

Workstation

- In-house pool traceable to

commercial polyclonal

calibrators

20+

<10 = neg

10-19 = equivocal

20-60 = positive

>60 = strong positive

11 dRVVT

+50:50 mix

Screen/confirm

Life Diagnostics

STAR Evolution

Stago

70 normal donors Precision Biologic weak

control Lupus

11 APTT

+50:50 mix

PTT-LA

Stago

STAR Evolution

Stago


control Lupus

WHO/BS/2014.2244

11 APTT

50:50 mix only

STAClot LA Stago

+buffer or phospholipid

(screen/confirm)

STAR Evolution

Stago


control Lupus

12 dRVVT LupoTek

Detection VL

Correction VL

R2 Diagnostics

STA compact

Stago

Precision Biologics Pooled normal

plasma

R2 Diagnostics PlasmaCon N

Sample/PNP ratio cut off 1.30

R2 Diagnostics PlasmaCon

LA

12 KCT

+50:50 mix

LupoTek KCT

R2 Diagnostics

STA compact

Stago

Precision Biologics Pooled normal

plasma

R2 Diagnostics PlasmaCon N

Ronser index: mix-PNP/sample

Cut-off 0.16

R2 Diagnostics PlasmaCon

LA

13 dRVVT

+50:50 mix

Screen/confirm HemosIL


ACL TOP 300,

Instrumentation

Laboratory

PPP local pool

20 donors

Mix/PPP ratio <1.16

Positive local

1 donor

Mix/PPP ratio <1.16

13 SCT

+50:50 mix

SCT screen/confirm

HemosIL


ACL TOP 300,

Instrumentation

Laboratory

PPP local pool

20 donors

Mix/PPP ratio <1.22

Positive local

1 donor

Mix/PPP ratio <1.22

14 dRVVT

+50:50 mix

LAC-S & LAC-C HemosIL


ACL TOP 500,

Instrumentation

Laboratory

Normal C HemosIL (PPP)

0.9-1.1 normal ratio

LA positive HemosIL

≥1.4 normal ratio

14 SCT

+50:50 mix

SCT HemosIL


ACL TOP 500,

Instrumentation

Laboratory

Normal C HemosIL (PPP)

0.84-1.16 normal ratio

LA positive HemosIL

≥1.4 normal ratio

15 dRVVT

+50:50 mix

Hemoclot screen & confirm

Hyphen-Biomed

STAR, Stago PPP Cryocheck

20 donors

35-45 s

Positive Cryocheck

0.95-1.23

15a APTT Cephen 5 LR

Hyphen-Biomed


20 donors

35-45 s

Cryocheck Positive

25.9-41.7 s

15b APTT APTT-LS

Cephen 2.5 LS


20 donors

Cryocheck Positive

25.9-41.7 s

WHO/BS/2014.2244

Hyphen-Biomed 35-45 s

16 dRVVT

+50:50 mix

DVV test & confirm

Sekisui Diagnostics

Siemens BCS LA normal Sekisui Diagnostics LA Abnormal Sekisui

Diagnostics

16 dPT

+50:50 mix

Acticlot dPT

Sekisui Diagnostics

Siemens BCS LA normal Sekisui Diagnostics LA Abnormal Sekisui

Diagnostics

17 dRVVT Technoclot screen/confirm

Technoclone

Ceveron,

Technoclone

Negative PPP Control -

Technoclone

Positive Control –

Technoclone 1.40-2.34

Screen 68-92

Confirm 36.5-49.5

17 APTT

(modified)

LA test

Technoclone

PPP, PPP + sample mix &

Sample only are run.

Mix-negative/sample x 100

= LCA index. LCA >15 =

positive)

Ceveron,

Technoclone

Negative PPP Control -

Technoclone

Positive Control –

Technoclone

29-49 s

18a dRVVT

+50:50 mix

Unicorn Diagnostics

dRVVT kit, Pathway

Diagnostics

KC4 Normal pool with kit In-house

18 dPT

+50:50 mix

dPT kit

American Diagnostica

KC4 Provided with kit Provided with kit

18b dRVVT

+50:50 mix

LA1 LA2

Siemens

KC4 PPP – Pathway Diagnostics Siemens LA High, LA Low

18 APTT

+50:50 mix

Actin FSL

Siemens

KC4 PPP – Pathway Diagnostics Siemens LA High, LA Low

19 dRVVT

50:50 mix only

STAClot screen/confirm

Stago

STAR Rack

Evolution, Stago

Normal Pool

350 donors

34.1-36.9 s

Patient pool

15 donors

1.67-1.97 ratio

19 APTT

50:50 mix only

Actin FS

Siemens

STAR Rack

Evolution, Stago

Normal Pool

350 donors

25.8-29.3 s

Patient pool

15 donors

1.06-1.23 ratio (positive/NP)

WHO/BS/2014.2244

19 APTT

50:50 mix only

STA PTT LA

Stago

STAR Rack

Evolution, Stago

Normal Pool

350 donors

31.9-35.9 s

Patient pool

15 donors

1.41-1.81 ratio (positive/NP)

WHO/BS/2014.2244

Appendix 3: Laboratory results DRVVT

Laboratory 1

Against laboratory PNP Against A

Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 0.96 1.06 1.12 0.95 -5.58

Day 2 0.95 1.07 1.14 0.94 -6.58

Day 3 0.97 1.08 1.15 0.94 -6.68

mean 0.96 1.07 1.14 0.94 -6.28

CV 0.83 0.84 1.37 0.58 -9.73

Sample A

Day 1 0.94 0.89 1.02 1.06 5.28

Day 2 0.94 0.88 1.01 1.07 6.18

Day 3 0.93 0.87 1.03 1.07 6.26

mean 0.94 0.88 1.02 1.06 5.91

CV 0.84 1.37 0.93 0.58 9.19

Sample B

Day 1 1.65 0.93 1.70 1.76 43.31 1.75 1.04 1.67 40.15

Day 2 1.63 0.92 1.68 1.76 43.21 1.74 1.05 1.65 39.47

Day 3 1.66 0.94 1.72 1.77 43.60 1.79 1.08 1.66 39.83

mean 1.64 0.93 1.70 1.77 43.37 1.76 1.06 1.66 39.82

CV 1.06 0.73 1.16 0.36 0.47 1.67 1.66 0.57 0.86

Sample C

Day 1 2.14 1.01 2.04 2.12 52.84 2.27 1.13 2.01 50.21

Day 2 2.14 1.01 2.03 2.13 53.00 2.29 1.15 2.00 49.91

Day 3 2.22 2.40

mean 2.17 2.32

CV 2.21 3.02

Sample Z

Day 1 1.28 0.99 1.24 1.29 22.56 1.35 1.11 1.22 18.24

Day 2 1.30 0.98 1.26 1.33 24.60 1.38 1.11 1.24 19.64

Day 3 1.31 0.99 1.28 1.32 24.39 1.42 1.14 1.24 19.33

mean 1.29 0.99 1.26 1.31 23.85 1.38 1.12 1.24 19.07

CV 1.41 0.80 1.41 1.46 4.71 2.24 1.69 0.91 3.86

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.30 1.11 1.99 2.07 51.68 2.44 1.24 1.96 48.98

Day 2 2.27 1.13 1.91 2.00 50.06 2.42 1.29 1.88 46.77

Day 3 2.30 1.10 2.01 2.08 51.97 2.48 1.27 1.95 48.76

mean 2.29 1.12 1.97 2.05 51.24 2.45 1.27 1.93 48.17

CV 0.80 1.33 2.91 2.09 2.01 1.17 1.77 2.32 2.53

WHO/BS/2014.2244

Laboratory 2


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1

Day 2

Day 3

mean

CV

Sample A

Day 1 0.93 0.94 1.01 0.99 -1.28

Day 2 0.95 0.95 1.02 1.00 -5.57

Day 3 0.94 0.93 1.03 1.01 -5.80

mean 0.94 0.94 1.02 1.00 -4.21

CV 0.01 0.01 0.01 0.01 -0.60

Sample B

Day 1 1.35 0.97 1.43 1.39 28.28 1.46 1.03 1.41 74.73

Day 2 1.35 0.99 1.40 1.36 61.45 1.42 1.04 1.37 69.26

Day 3 1.35 0.96 1.43 1.40 63.85 1.44 1.04 1.39 72.69

mean 1.35 0.97 1.42 1.39 51.20 1.44 1.04 1.39 72.22

CV 0.00 0.01 0.01 0.01 0.39 0.01 0.01 0.02 0.04

Sample C

Day 1 1.66 1.01 1.69 1.65 39.42 1.79 1.07 1.67 118.69

Day 2 1.66 1.04 1.64 1.60 103.75 1.76 1.10 1.60 113.32

Day 3 1.65 1.00 1.68 1.65 104.56 1.77 1.08 1.64 115.53

mean 1.66 1.02 1.67 1.63 82.58 1.77 1.08 1.64 115.85

CV 0.00 0.02 0.02 0.02 0.45 0.01 0.01 0.02 0.02

Sample Z

Day 1 1.24 0.97 1.31 1.28 21.90 1.33 1.03 1.30 56.32

Day 2 1.24 0.99 1.28 1.25 44.33 1.31 1.04 1.26 51.53

Day 3 1.24 0.96 1.32 1.29 46.62 1.33 1.03 1.28 54.66

mean 1.24 0.97 1.31 1.28 37.62 1.32 1.04 1.28 54.17

CV 0.00 0.01 0.01 0.01 0.36 0.01 0.01 0.02 0.04

Local Negative

Day 1 1.03 1.07 1.06 1.01 8.74

Day 2 1.02 1.06 1.05 1.00 5.87

Day 3 1.02 1.07 1.08 0.99 6.24

mean 1.02 1.07 1.06 1.00 6.95

CV 0.00 0.01 0.01 0.01 0.22

Local Positive

Day 1 1.80 1.07 1.73 1.69 40.83 1.94 1.13 1.71 135.36

Day 2 1.88 1.07 1.80 1.76 131.00 1.99 1.13 1.76 141.79

Day 3 1.78 1.05 1.73 1.69 119.22 1.90 1.13 1.68 131.09

mean 1.82 1.06 1.75 1.71 97.02 1.94 1.13 1.72 136.08

CV 0.03 0.01 0.02 0.02 0.51 0.02 0.00 0.02 0.04

WHO/BS/2014.2244

Laboratory 3


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1

Day 2

Day 3

mean

CV

Sample A

Day 1 1.03 0.97 1.08 1.07 6.35

Day 2 0.92 0.82 1.07 1.12 10.54

Day 3 1.02 1.02 1.09 1.00 0.37

mean 0.99 0.93 1.08 1.06 5.75

CV 6.45 10.98 0.77 5.38 88.84

Sample B

Day 1 1.47 0.99 1.49 1.48 32.29 1.42 1.03 1.38 27.70

Day 2 1.29 0.86 1.44 1.51 33.66 1.41 1.05 1.35 25.84

Day 3 1.43 1.10 1.40 1.30 22.99 1.41 1.09 1.29 22.70

mean 1.40 0.99 1.44 1.43 29.65 1.41 1.05 1.34 25.42

CV 6.66 12.58 2.92 7.91 19.59 0.65 2.79 3.37 9.96

Sample C

Day 1 1.79 1.13 1.60 1.58 36.86 1.74 1.17 1.48 32.59

Day 2 1.60 0.89 1.71 1.79 44.22 1.75 1.09 1.60 37.65

Day 3 1.75 1.14 1.66 1.53 34.70 1.72 1.13 1.53 34.45

mean 1.71 1.06 1.66 1.64 38.59 1.73 1.13 1.54 34.90

CV 5.91 13.42 3.57 8.45 12.94 0.91 3.65 3.97 7.33

Sample Z

Day 1 1.52 0.98 1.56 1.55 35.48 1.47 1.01 1.45 31.11

Day 2 1.33 0.80 1.60 1.67 40.09 1.45 0.97 1.49 33.03

Day 3 1.53 1.03 1.61 1.49 32.68 1.50 1.01 1.48 32.43

mean 1.46 0.93 1.59 1.57 36.08 1.47 1.00 1.47 32.19

CV 7.52 12.95 1.47 5.95 10.37 1.41 2.20 1.44 3.06

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1

Day 2

Day 3

mean

CV

WHO/BS/2014.2244

Lab 4

DRVVT 80:20 mix

Day 1 A

Samples

Clotting times (s)

1 2 Mean

Local normal platelet poor

Healthy donor mix 40.2 39.6 39.9

Number of donors: 1

Reference range: 50.5 s

A mix 42.2 41 41.6

B mix 46.1 45.4 45.6

C mix 50.8 50.2 50.5

Z mix 43.2 42.7 42.95


control mix 99.4 98.3 98.85

Source: Patient plasma

Number of donors: 1

Reference range: 99

Day 1 B

Samples

Clotting times (s)

1 2 Mean



Number of donors: 1

A mix 37.6 37.6 37.6

B mix 37.9 37.6 37.8

C mix 38.3 37.7 38

Z mix 38 36.8 37.4


control mix 44.8 43.9 44.4


Number of donors: 1

WHO/BS/2014.2244

Day 2 A

Samples

Clotting times (s)

1 2 Mean



Number of donors: 1

Reference range: 50.5 s

A mix 42.3 41.1 41.7

B mix 44.6 46.5 45.69

C mix 52.1 53.4 52.8

Z mix 44.2 49.5 46.9


control mix 104.7 99.9 102.3


Number of donors: 1

Reference range: 102.3

Day 2 B

Samples

Clotting times (s)

1 2 Mean



Number of donors: 1

A mix 37.8 37.6 37.7

B mix 37.8 39.4 38.6

C mix 38.2 37.5 37.9

Z mix 37.3 35.6 36.5


control mix 44.3 42.1 43.2


Number of donors: 1

WHO/BS/2014.2244

Day 3 A

Samples

Clotting times (s)

1 2 Mean



Number of donors: 1

Reference range: 49 s

A mix 41.6 41 41.3

B mix 45.5 45.6 45.55

C mix 52.1 50.5 51.3

Z mix 43.8 42.1 42.95


control mix 100.1 101.4 100.8


Number of donors: 1


Day 3 B

Samples

Clotting times (s)

1 2 Mean



Number of donors: 1

A mix 38.8 37.3 38.1

B mix 37.7 37.1 37.4

C mix 37.5 37.2 37.4

Z mix 37.5 37.2 37.4


control mix 44.3 42.1 43.2


Number of donors: 1

WHO/BS/2014.2244

Laboratory 5


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.07 0.97 0.96 1.01 0.56

Day 2 1.03 0.98 0.98 1.01 0.71

Day 3 1.10 1.00 0.94 1.06 5.59

mean 1.07 0.98 0.96 1.02 2.29

CV 3.48 1.61 1.72 2.98 125.38

Sample A

Day 1 1.03 1.04 1.06 0.99 -0.56

Day 2 1.02 1.02 1.02 0.99 -0.71

Day 3 1.00 1.06 1.04 0.94 -5.92

mean 1.02 1.04 1.04 0.98 -2.40

CV 1.61 1.72 1.96 2.93 -127.34

Sample B

Day 1 1.50 1.08 1.48 1.39 27.90 1.46 1.04 1.39 28.30

Day 2 1.51 1.07 1.45 1.41 29.08 1.49 1.05 1.42 29.58

Day 3 1.46 1.07 1.50 1.36 26.60 1.46 1.01 1.44 30.71

mean 1.49 1.07 1.48 1.39 27.86 1.47 1.03 1.42 29.53

CV 1.92 0.74 1.77 1.72 4.45 1.14 1.96 1.71 4.08

Sample C

Day 1 1.80 1.10 1.74 1.63 38.53 1.74 1.06 1.64 38.87

Day 2 1.87 1.10 1.75 1.70 41.20 1.84 1.08 1.71 41.62

Day 3 1.83 1.12 1.80 1.63 38.68 1.83 1.06 1.73 42.11

mean 1.83 1.11 1.76 1.65 39.47 1.80 1.07 1.69 40.87

CV 2.06 1.00 1.83 2.52 3.81 3.08 0.79 2.91 4.27

Sample Z

Day 1 1.39 1.05 1.41 1.32 24.05 1.34 1.01 1.32 24.47

Day 2 1.39 1.06 1.35 1.31 23.88 1.37 1.03 1.32 24.42

Day 3 1.35 1.06 1.40 1.27 21.29 1.35 1.00 1.35 25.69

mean 1.37 1.06 1.39 1.30 23.07 1.35 1.02 1.33 24.86

CV 1.56 0.49 2.19 1.99 6.70 0.93 1.48 0.97 2.90

Local Negative

Day 1 1.09 1.09 1.07 1.00 -0.25 1.05 1.05 1.00 0.31

Day 2 1.06 1.08 1.02 0.99 -1.45 1.05 1.05 0.99 -0.73

Day 3 1.04 1.10 1.05 0.95 -5.45 1.04 1.04 1.00 0.45

mean 1.06 1.09 1.04 0.98 -2.38 1.05 1.05 1.00 0.01

CV 2.08 1.09 2.50 2.63 -114.47 0.51 0.67 0.64 5877.12

Local Positive

Day 1 1.92 1.14 1.80 1.68 40.48 1.85 1.10 1.69 40.81

Day 2 2.00 1.19 1.73 1.68 40.57 1.97 1.16 1.69 40.99

Day 3 1.91 1.21 1.74 1.58 36.65 1.91 1.14 1.67 40.19

mean 1.94 1.18 1.76 1.65 39.23 1.91 1.13 1.69 40.66

CV 2.63 3.01 1.96 3.61 5.71 2.97 2.87 0.70 1.03

WHO/BS/2014.2244

Laboratory 6


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.06 0.97 1.03 0.94 -6.01

Day 2 1.07 0.97 1.04 0.94 -6.95

Day 3 1.05 0.96 1.06 0.91 -10.30

mean 1.06 0.97 1.04 0.93 -7.75

CV 0.78 0.74 1.45 2.08 -29.12

Sample A

Day 1 1.03 0.97 1.12 1.06 5.67

Day 2 1.03 0.96 1.14 1.07 6.50

Day 3 1.04 0.95 1.16 1.10 9.34

mean 1.04 0.96 1.14 1.08 7.17

CV 0.74 1.44 1.66 2.10 26.88

Sample B

Day 1 1.80 1.02 1.86 1.76 43.19 1.74 1.05 1.66 39.78

Day 2 1.84 1.01 1.96 1.83 45.40 1.79 1.04 1.71 41.60

Day 3 1.83 0.99 1.94 1.84 45.72 1.75 1.05 1.67 40.12

mean 1.82 1.01 1.92 1.81 44.77 1.76 1.05 1.68 40.50

CV 1.23 1.41 2.56 2.46 3.07 1.42 0.24 1.64 2.39

Sample C

Day 1 2.20 1.09 2.13 2.02 50.40 2.13 1.12 1.90 47.43

Day 2 2.27 1.08 2.25 2.11 52.66 2.21 1.12 1.98 49.37

Day 3 2.23 1.06 2.22 2.11 52.62 2.14 1.12 1.91 47.74

mean 2.24 1.08 2.20 2.08 51.89 2.16 1.12 1.93 48.18

CV 1.52 1.58 2.84 2.64 2.48 1.87 0.21 2.03 2.16

Sample Z

Day 1 1.53 0.96 1.68 1.59 37.04 1.48 0.99 1.50 33.26

Day 2 1.51 0.95 1.69 1.58 36.78 1.46 0.99 1.48 32.38

Day 3 1.50 0.94 1.68 1.60 37.40 1.44 0.99 1.45 30.96

mean 1.51 0.95 1.68 1.59 37.07 1.46 0.99 1.48 32.20

CV 1.04 1.25 0.30 0.50 0.85 1.51 0.22 1.71 3.61

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.04 1.05 2.06 1.94 48.55 1.97 1.08 1.83 45.46

Day 2 2.00 1.04 2.05 1.92 48.03 1.95 1.08 1.80 44.42

Day 3 2.05 1.04 2.07 1.97 49.16 1.97 1.10 1.78 43.93

mean 2.03 1.04 2.06 1.94 48.58 1.96 1.09 1.81 44.60

CV 1.25 0.33 0.35 1.11 1.17 0.71 1.30 1.42 1.76

WHO/BS/2014.2244

Laboratory 7


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 0.99 1.14 1.20 0.95 -5.33

Day 2 0.96 1.08 1.18 0.91 -9.51

Day 3 0.99 1.07 1.16 0.92 -8.42

mean 0.98 1.10 1.18 0.93 -7.75

CV 1.87 3.53 1.80 2.03 -27.99

Sample A

Day 1 0.88 0.83 1.04 1.05 5.06 0.82

Day 2 0.93 0.85 1.03 1.10 8.68 0.87

Day 3 0.94 0.86 1.05 1.08 7.76 0.86

mean 0.91 0.85 1.04 1.08 7.17 0.85

CV 3.47 1.80 0.64 2.01 26.30 3.35

Sample B

Day 1 1.27 0.90 1.41 1.42 29.61 1.02 1.45 1.07 1.35 25.86 1.16

Day 2 1.30 0.90 1.36 1.44 30.72 1.07 1.40 1.06 1.32 24.13 1.16

Day 3 1.35 0.91 1.42 1.48 32.30 1.07 1.44 1.05 1.36 26.60 1.14

mean 1.31 0.90 1.40 1.45 30.88 1.05 1.43 1.06 1.34 25.53 1.15

CV 2.85 0.89 2.33 1.96 4.38 2.93 1.66 0.92 1.69 4.97 0.94

Sample C

Day 1 2.20 1.09 2.13 2.02 50.40 1.17 1.72 1.17 1.47 32.10 1.33

Day 2 2.27 1.08 2.25 2.11 52.66 1.26 1.73 1.16 1.50 33.23 1.36

Day 3 2.23 1.06 2.22 2.11 52.62 1.23 1.79 1.16 1.54 34.89 1.31

mean 2.24 1.08 2.20 2.08 51.89 1.22 1.75 1.16 1.50 33.40 1.34

CV 1.52 1.58 2.84 2.64 2.48 3.84 1.94 0.55 2.12 4.20 1.83

Sample Z

Day 1 1.53 0.96 1.68 1.59 37.04 0.99 1.26 1.01 1.25 19.81 1.12

Day 2 1.51 0.95 1.69 1.58 36.78 1.06 1.26 1.02 1.24 19.31 1.14

Day 3 1.50 0.94 1.68 1.60 37.40 1.04 1.28 1.01 1.27 21.18 1.11

mean 1.51 0.95 1.68 1.59 37.07 1.03 1.27 1.01 1.25 20.10 1.13

CV 1.04 1.25 0.30 0.50 0.85 3.78 0.73 0.49 1.22 4.81 1.35

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.04 1.05 2.06 1.94 48.55 1.97 1.08 1.83 45.46

Day 2 2.00 1.04 2.05 1.92 48.03 1.95 1.08 1.80 44.42

Day 3 2.05 1.04 2.07 1.97 49.16 1.97 1.10 1.78 43.93

mean 2.03 1.04 2.06 1.94 48.58 1.96 1.09 1.81 44.60

CV 1.25 0.33 0.35 1.11 1.17 0.71 1.30 1.42 1.76

WHO/BS/2014.2244

Laboratory 8a


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.04 1.03 1.05 0.98 -2.22

Day 2 1.05 1.04 1.04 1.00 -0.48

Day 3 1.05 1.01 1.04 0.97 -2.75

mean 1.05 1.03 1.04 0.98 -1.82

CV 0.40 1.11 0.52 1.17 -65.39

Sample A

Day 1 0.97 0.95 1.07 1.02 2.17

Day 2 0.97 0.96 1.06 1.00 0.48

Day 3 0.99 0.96 1.08 1.03 2.67

mean 0.97 0.96 1.07 1.02 1.77

CV 1.11 0.52 1.01 1.17 64.89

Sample B

Day 1 1.45 0.98 1.55 1.48 32.52 1.49 1.03 1.45 31.02

Day 2 1.46 0.99 1.55 1.48 32.33 1.51 1.03 1.47 32.01

Day 3 1.47 0.99 1.56 1.48 32.62 1.49 1.03 1.44 30.77

mean 1.46 0.98 1.55 1.48 32.49 1.50 1.03 1.45 31.27

CV 0.81 0.73 0.37 0.21 0.44 0.76 0.34 0.96 2.10

Sample C

Day 1 1.81 1.03 1.83 1.75 42.89 1.86 1.08 1.71 41.63

Day 2 1.86 1.05 1.87 1.77 43.66 1.93 1.09 1.77 43.39

Day 3 1.85 1.04 1.87 1.78 43.86 1.87 1.08 1.73 42.32

mean 1.84 1.04 1.85 1.77 43.47 1.89 1.09 1.74 42.45

CV 1.54 0.82 1.26 0.90 1.17 1.97 0.51 1.55 2.09

Sample Z

Day 1 1.42 0.97 1.52 1.46 31.56 1.46 1.02 1.43 30.04

Day 2 1.37 0.97 1.48 1.41 28.84 1.42 1.01 1.40 28.50

Day 3 1.40 0.98 1.49 1.42 29.69 1.42 1.02 1.38 27.75

mean 1.39 0.97 1.50 1.43 30.03 1.43 1.02 1.40 28.76

CV 1.81 0.77 1.60 2.00 4.63 1.58 0.59 1.64 4.05

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.09 1.11 1.96 1.88 46.84 2.15 1.17 1.84 45.66

Day 2 2.08 1.11 1.96 1.87 46.44 2.15 1.16 1.86 46.18

Day 3 2.10 1.11 1.98 1.89 46.96 2.12 1.16 1.83 45.50

mean 2.09 1.11 1.97 1.88 46.75 2.14 1.16 1.84 45.78

CV 0.43 0.09 0.44 0.51 0.58 0.73 0.47 0.66 0.78

WHO/BS/2014.2244

Laboratory 8b


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 0.92 1.00 1.02 0.98 -2.56

Day 2 0.93 1.00 1.01 0.99 -1.26

Day 3 0.94 0.99 1.02 0.97 -2.58

mean 0.93 1.00 1.02 0.98 -2.13

CV 0.79 0.27 0.52 0.74 -35.37

Sample A

Day 1 1.00 0.98 0.94 1.03 2.50

Day 2 1.00 0.99 0.94 1.01 1.25

Day 3 1.01 0.98 0.96 1.03 2.51

mean 1.00 0.98 0.95 1.02 2.09

CV 0.27 0.52 1.10 0.74 34.84

Sample B

Day 1 1.55 1.00 1.43 1.55 35.43 1.55 1.03 1.51 33.78

Day 2 1.58 1.02 1.44 1.55 35.58 1.58 1.03 1.53 34.77

Day 3 1.55 0.98 1.48 1.59 36.96 1.55 1.00 1.55 35.33

mean 1.56 1.00 1.45 1.56 35.99 1.56 1.02 1.53 34.63

CV 1.10 2.00 2.07 1.33 2.34 1.33 1.69 1.20 2.28

Sample C

Day 1 1.96 1.06 1.70 1.85 45.98 1.95 1.08 1.81 44.60

Day 2 2.01 1.08 1.72 1.85 46.03 2.01 1.10 1.83 45.35

Day 3 1.99 1.07 1.73 1.85 46.04 1.98 1.10 1.81 44.65

mean 1.98 1.07 1.72 1.85 46.02 1.98 1.09 1.81 44.87

CV 1.26 1.21 0.84 0.06 0.07 1.36 0.80 0.76 0.93

Sample Z

Day 1 1.47 0.99 1.37 1.48 32.60 1.47 1.01 1.45 30.88

Day 2 1.44 1.00 1.34 1.44 30.68 1.44 1.01 1.42 29.81

Day 3 1.45 1.00 1.36 1.45 31.07 1.44 1.02 1.41 29.29

mean 1.45 1.00 1.35 1.46 31.45 1.45 1.01 1.43 29.99

CV 1.16 0.50 1.04 1.49 3.23 1.06 0.63 1.16 2.70

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.19 1.13 1.79 1.95 48.65 2.19 1.15 1.90 47.34

Day 2 2.20 1.12 1.81 1.95 48.79 2.20 1.14 1.93 48.14

Day 3 2.22 1.13 1.84 1.96 49.08 2.21 1.15 1.91 47.77

mean 2.20 1.13 1.81 1.95 48.84 2.20 1.15 1.91 47.75

CV 0.62 0.22 1.21 0.43 0.45 0.43 0.68 0.77 0.84

WHO/BS/2014.2244

Laboratory 8c


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.06 0.99 1.01 0.98 -2.53

Day 2 1.06 1.00 1.02 0.99 -1.46

Day 3 1.06 0.99 1.02 0.97 -2.85

mean 1.06 0.99 1.02 0.98 -2.28

CV 0.19 0.82 0.43 0.71 -31.98

Sample A

Day 1 1.01 0.99 1.09 1.03 2.47

Day 2 1.00 0.98 1.07 1.01 1.44

Day 3 1.01 0.98 1.09 1.03 2.77

mean 1.01 0.98 1.09 1.02 2.22

CV 0.82 0.43 0.89 0.71 31.42

Sample B

Day 1 1.61 1.03 1.66 1.56 35.92 1.58 1.04 1.52 34.30

Day 2 1.57 1.02 1.64 1.55 35.42 1.58 1.03 1.53 34.48

Day 3 1.58 1.02 1.65 1.55 35.46 1.57 1.04 1.51 33.62

mean 1.59 1.02 1.65 1.55 35.60 1.58 1.04 1.52 34.13

CV 1.03 0.60 0.58 0.43 0.78 0.53 0.34 0.69 1.33

Sample C

Day 1 1.99 1.09 1.94 1.83 45.25 1.97 1.10 1.78 43.87

Day 2 1.96 1.09 1.90 1.79 44.28 1.97 1.11 1.77 43.47

Day 3 2.00 1.09 1.96 1.85 45.81 1.99 1.11 1.79 44.27

mean 1.99 1.09 1.93 1.82 45.12 1.97 1.11 1.78 43.87

CV 1.07 0.40 1.56 1.40 1.71 0.55 0.36 0.71 0.91

Sample Z

Day 1 1.51 1.00 1.60 1.51 33.69 1.49 1.01 1.47 32.01

Day 2 1.43 1.00 1.51 1.43 30.03 1.44 1.02 1.41 29.01

Day 3 1.48 1.00 1.57 1.48 32.37 1.47 1.02 1.44 30.44

mean 1.47 1.00 1.56 1.47 32.03 1.46 1.02 1.44 30.49

CV 2.56 0.16 2.89 2.71 5.80 1.75 0.49 2.17 4.93

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.26 1.15 2.08 1.96 48.94 2.23 1.17 1.91 47.65

Day 2 2.20 1.15 2.03 1.92 47.93 2.21 1.17 1.89 47.17

Day 3 2.24 1.16 2.05 1.93 48.27 2.22 1.18 1.88 46.80

mean 2.23 1.15 2.06 1.94 48.38 2.22 1.17 1.89 47.21

CV 1.21 0.39 1.17 1.00 1.07 0.40 0.66 0.81 0.90

WHO/BS/2014.2244

Laboratory 9


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.10 0.96 0.95 1.02 1.78

Day 2 1.05 0.96 0.97 0.99 -1.52

Day 3 1.05 0.95 0.94 1.00 0.25

mean 1.06 0.96 0.95 1.00 0.17

CV 2.87 0.97 1.80 1.65 974.28

Sample A

Day 1 1.04 1.06 1.08 0.98 -1.81 1.01

Day 2 1.04 1.03 1.06 1.02 1.50 1.02

Day 3 1.06 1.06 1.04 1.00 -0.25 1.01

mean 1.05 1.05 1.06 1.00 -0.19 1.01

CV 0.97 1.78 1.72 1.65 -880.50 0.74

Sample B

Day 1 1.44 1.10 1.44 1.31 23.60 1.26 1.39 1.04 1.33 24.96 1.21

Day 2 1.46 1.11 1.37 1.31 23.60 1.27 1.40 1.09 1.29 22.44 1.22

Day 3 1.50 1.10 1.42 1.36 26.53 1.31 1.42 1.04 1.36 26.71 1.24

mean 1.47 1.11 1.41 1.33 24.58 1.28 1.40 1.06 1.33 24.70 1.22

CV 1.92 0.68 2.55 2.27 6.89 2.18 0.96 2.49 2.84 8.71 1.22

Sample C

Day 1 1.64 1.17 1.54 1.40 28.56 1.42 1.58 1.11 1.43 29.83 1.37

Day 2 1.70 1.17 1.51 1.45 30.85 1.45 1.63 1.14 1.42 29.80 1.39

Day 3 1.69 1.15 1.54 1.47 32.04 1.46 1.59 1.08 1.48 32.21 1.38

mean 1.67 1.16 1.53 1.44 30.48 1.44 1.60 1.11 1.44 30.61 1.38

CV 1.79 1.30 0.94 2.52 5.80 1.35 1.55 2.78 2.01 4.51 0.95

Sample Z

Day 1 1.25 1.11 1.24 1.12 11.01 1.12 1.20 1.05 1.14 12.60 1.08

Day 2 1.30 1.12 1.22 1.16 13.97 1.16 1.25 1.09 1.14 12.66 1.12

Day 3 1.30 1.10 1.23 1.18 15.06 1.15 1.22 1.04 1.18 15.27 1.09

mean 1.28 1.11 1.23 1.15 13.35 1.14 1.23 1.06 1.16 13.51 1.09

CV 2.26 0.90 0.79 2.39 15.69 1.73 1.91 2.62 1.78 11.31 1.69

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.45 1.15 1.38 1.25 20.22 1.25 1.39 1.09 1.28 21.64 1.21

Day 2 1.51 1.15 1.38 1.32 24.01 1.29 1.45 1.12 1.30 22.86 1.24

Day 3 1.48 1.12 1.38 1.32 24.28 1.31 1.40 1.05 1.32 24.47 1.24

mean 1.48 1.14 1.38 1.30 22.84 1.28 1.41 1.09 1.30 22.99 1.23

CV 2.14 1.68 0.15 2.90 9.95 2.20 2.21 2.91 1.85 6.18 1.49

WHO/BS/2014.2244

Laboratory 10


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.10 1.03 1.03 1.00 -0.29 1.03

Day 2 1.12 1.05 1.04 1.01 1.47 1.05

Day 3 1.07 0.99 1.01 0.97 -2.83 1.00

mean 1.09 1.02 1.03 0.99 -0.55 1.03

CV 2.41 3.36 1.23 2.14 -392.82 2.45

Sample A

Day 1 0.97 0.97 1.10 1.00 0.29 0.97

Day 2 0.95 0.96 1.10 0.99 -1.49 0.95

Day 3 1.01 0.99 1.10 1.03 2.76 1.00

mean 0.98 0.97 1.10 1.01 0.52 0.97

CV 3.39 1.24 0.27 2.15 412.38 2.47

Sample B

Day 1 1.63 1.00 1.79 1.63 38.56 1.33 1.68 1.03 1.62 38.38 1.38

Day 2 1.64 1.01 1.82 1.63 38.57 1.31 1.73 1.05 1.65 39.47 1.38

Day 3 1.75 1.02 1.82 1.71 41.49 1.38 1.73 1.04 1.66 39.84 1.38

mean 1.67 1.01 1.81 1.65 39.54 1.34 1.71 1.04 1.65 39.23 1.38

CV 4.02 1.19 1.16 2.84 4.28 2.70 1.70 0.61 1.24 1.93 0.32

Sample C

Day 1 2.02 1.05 2.12 1.93 48.18 1.63 2.08 1.08 1.92 48.03 1.69

Day 2 2.03 1.07 2.12 1.90 47.27 1.60 2.14 1.11 1.92 48.05 1.68

Day 3 2.18 1.07 2.16 2.03 50.73 1.70 2.15 1.09 1.97 49.33 1.70

mean 2.08 1.06 2.13 1.95 48.73 1.64 2.12 1.09 1.94 48.47 1.69

CV 4.17 1.21 1.21 3.54 3.67 3.09 1.64 1.41 1.46 1.54 0.64

Sample Z

Day 1 1.41 1.02 1.52 1.39 27.94 1.20 1.45 1.05 1.38 27.73 1.24

Day 2 1.39 0.97 1.60 1.43 29.94 1.18 1.46 1.01 1.45 30.97 1.24

Day 3 1.47 0.97 1.62 1.52 34.34 1.21 1.45 0.98 1.48 32.48 1.21

mean 1.42 0.98 1.58 1.45 30.74 1.20 1.46 1.01 1.44 30.39 1.23

CV 3.04 2.88 3.32 4.81 10.65 1.26 0.40 3.50 3.45 7.98 1.27

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.01 1.02 2.16 1.97 49.13 1.76 2.06 1.05 1.96 48.99 1.82

Day 2 2.20 1.10 2.23 1.99 49.73 2.02 2.32 1.15 2.02 50.47 2.12

Day 3 2.18 1.06 2.18 2.05 51.12 2.08 2.15 1.08 1.99 49.74 2.08

mean 2.13 1.06 2.19 2.00 50.00 1.95 2.18 1.09 1.99 49.73 2.00

CV 4.94 3.97 1.59 2.06 2.04 8.50 5.92 4.47 1.48 1.49 7.98

WHO/BS/2014.2244

Laboratory 11


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.03 0.92 0.98 0.94 -6.52 0.92

Day 2 1.03 0.90 0.95 0.95 -5.54 0.90

Day 3 1.03 0.92 0.98 0.94 -5.94 0.92

mean 1.03 0.92 0.97 0.94 -6.00 0.92

CV 0.34 1.14 1.56 0.46 -8.15 1.14

Sample A

Day 1 1.08 1.02 1.09 1.07 6.12 1.03

Day 2 1.11 1.05 1.09 1.06 5.25 1.06

Day 3 1.09 1.02 1.09 1.06 5.61 1.05

mean 1.09 1.03 1.09 1.06 5.66 1.05

CV 1.14 1.57 0.19 0.46 7.69 1.32

Sample B

Day 1 1.62 1.07 1.55 1.51 33.87 1.29 1.50 1.06 1.42 29.56 1.19

Day 2 1.63 1.09 1.55 1.50 33.27 1.32 1.47 1.04 1.42 29.57 1.20

Day 3 1.64 1.07 1.58 1.53 34.49 1.32 1.51 1.05 1.44 30.60 1.21

mean 1.63 1.08 1.56 1.51 33.88 1.31 1.49 1.05 1.43 29.91 1.20

CV 0.53 0.67 0.98 0.93 1.81 1.52 1.31 0.92 0.86 2.00 1.06

Sample C

Day 1 2.06 1.14 1.86 1.81 44.70 1.59 1.90 1.12 1.70 41.10 1.47

Day 2 2.05 1.17 1.81 1.75 42.91 1.60 1.85 1.11 1.66 39.75 1.44

Day 3 2.11 1.16 1.88 1.82 45.18 1.59 1.94 1.13 1.72 41.93 1.46

mean 2.07 1.15 1.85 1.79 44.26 1.59 1.90 1.12 1.69 40.92 1.46

CV 1.59 1.35 2.03 2.13 2.70 0.34 2.38 0.55 1.86 2.69 0.80

Sample Z

Day 1 1.58 1.02 1.59 1.55 35.33 1.22 1.46 1.00 1.45 31.12 1.13

Day 2 1.57 1.03 1.57 1.52 34.19 1.24 1.42 0.98 1.44 30.54 1.12

Day 3 1.58 1.02 1.59 1.54 34.98 1.23 1.45 1.00 1.45 31.12 1.13

mean 1.57 1.02 1.58 1.53 34.84 1.23 1.44 1.00 1.45 30.93 1.13

CV 0.36 0.57 0.67 0.89 1.68 0.59 1.49 1.02 0.48 1.08 0.62

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.69 1.14 1.52 1.48 32.21 1.30 1.56 1.12 1.38 27.79 1.20

Day 2 1.65 1.14 1.49 1.44 30.75 1.28 1.49 1.09 1.37 26.91 1.16

Day 3 1.67 1.14 1.51 1.46 31.56 1.31 1.54 1.11 1.38 27.50 1.20

mean 1.67 1.14 1.51 1.46 31.51 1.30 1.53 1.11 1.38 27.40 1.19

CV 1.05 0.07 0.79 1.07 2.32 0.81 2.14 1.52 0.62 1.63 1.86

WHO/BS/2014.2244

Laboratory 12


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.18 0.77 0.92 0.84 -18.59

Day 2 1.17 0.77 0.91 0.84 -18.72

Day 3 1.16 0.79 0.92 0.86 -16.08

mean 1.17 0.78 0.92 0.85 -17.80

CV 0.78 1.49 0.23 1.27 -8.35

Sample A

Day 1 1.29 1.09 1.40 1.19 15.68

Day 2 1.30 1.09 1.39 1.19 15.77

Day 3 1.26 1.09 1.35 1.16 13.86

mean 1.29 1.09 1.38 1.18 15.10

CV 1.48 0.23 1.92 1.26 7.14

Sample B

Day 1 1.92 1.15 1.97 1.66 39.85 1.48 1.06 1.40 28.66

Day 2 1.94 1.13 2.02 1.72 41.93 1.50 1.03 1.45 31.06

Day 3 1.94 1.15 1.96 1.68 40.54 1.53 1.06 1.45 30.97

mean 1.93 1.14 1.98 1.69 40.77 1.50 1.05 1.43 30.23

CV 0.70 1.23 1.62 1.80 2.60 1.80 1.42 1.93 4.50

Sample C

Day 1 2.34 1.22 2.26 1.91 47.75 1.81 1.12 1.61 38.04

Day 2 2.32 1.19 2.29 1.96 48.91 1.79 1.09 1.65 39.34

Day 3 2.27 1.21 2.20 1.89 47.00 1.80 1.11 1.63 38.47

mean 2.31 1.20 2.25 1.92 47.88 1.80 1.10 1.63 38.62

CV 1.45 1.45 2.18 1.85 2.01 0.47 1.55 1.09 1.73

Sample Z

Day 1 1.81 1.20 1.78 1.51 33.66 1.40 1.10 1.27 21.32

Day 2 1.78 1.18 1.77 1.51 33.76 1.37 1.08 1.27 21.36

Day 3 1.77 1.14 1.81 1.56 35.80 1.40 1.05 1.34 25.48

mean 1.79 1.17 1.79 1.52 34.41 1.39 1.07 1.29 22.72

CV 1.00 2.62 1.30 1.86 3.51 1.24 2.45 3.14 10.50

Local Negative

Day 1 1.17 1.06 1.31 1.10 9.38 0.90 0.97 0.93 -7.47

Day 2 1.15 1.04 1.30 1.11 9.75 0.89 0.95 0.93 -7.14

Day 3 1.16 1.06 1.28 1.10 8.75 0.92 0.97 0.94 -5.93

mean 1.16 1.05 1.29 1.10 9.30 0.90 0.96 0.94 -6.84

CV 0.51 0.75 1.17 0.56 5.46 1.43 0.94 0.76 -11.86

Local Positive

Day 1 2.52 1.26 2.36 2.00 49.92 1.95 1.16 1.68 40.61

Day 2 2.47 1.24 2.33 1.99 49.67 1.90 1.14 1.67 40.25

Day 3 2.57 1.26 2.37 2.04 50.89 2.03 1.16 1.75 42.99

mean 2.52 1.25 2.35 2.01 50.16 1.96 1.15 1.70 41.28

CV 1.99 0.96 0.97 1.30 1.28 3.39 1.13 2.57 3.61

WHO/BS/2014.2244

Laboratory 13


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.01

Day 2 1.03

Day 3 1.03

mean 1.02

CV 1.07

Sample A

Day 1 0.99

Day 2 0.97

Day 3 0.97

mean 0.98

CV 1.07

Sample B

Day 1 1.48 1.55 1.27 1.49 1.28

Day 2 1.43 1.50 1.23 1.47 1.26

Day 3 1.44 1.48 1.21 1.48 1.25

mean 1.45 1.51 1.24 1.48 1.26

CV 1.73 2.47 2.43 0.66 1.44

Sample C

Day 1 1.74 1.73 1.40 1.76 1.42

Day 2 1.78 1.80 1.53 1.83 1.58

Day 3 1.79 1.79 1.44 1.84 1.48

mean 1.77 1.77 1.46 1.81 1.49

CV 1.55 2.22 4.51 2.59 5.33

Sample Z

Day 1 1.30 1.35 1.18 1.32 1.20

Day 2 1.29 1.14 1.33 1.17

Day 3 1.31 1.11 1.35 1.14

mean 1.30 1.35 1.14 1.33 1.17

CV 0.92 3.16 1.40 2.16

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 5.64 2.80 5.69

Day 2 5.73 5.89

Day 3 5.63 5.79

mean 5.66 5.79

CV 0.97 1.71

WHO/BS/2014.2244

Laboratory 14


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.04 0.98 0.99 1.00 -0.23

Day 2 1.11 0.98 0.98 1.00 0.18

Day 3 1.08 0.97 0.98 0.99 -0.67

mean 1.08 0.98 0.98 1.00 -0.24

CV 3.37 0.64 0.31 0.43 -178.35

Sample A

Day 1 1.02 1.02 1.04 1.00 0.23 1.01

Day 2 1.02 1.02 1.11 1.00 -0.18 0.97

Day 3 1.03 1.02 1.09 1.01 0.67 0.99

mean 1.02 1.02 1.08 1.00 0.24 0.99

CV 0.64 0.31 3.23 0.43 178.80 2.03

Sample B

Day 1 1.44 1.03 1.45 1.40 28.48 1.24 1.42 1.02 1.40 28.32 1.22

Day 2 1.38 1.05 1.45 1.31 23.50 1.19 1.35 1.03 1.31 23.64 1.17

Day 3 1.39 1.05 1.44 1.33 24.58 1.22 1.35 1.03 1.32 24.07 1.18

mean 1.40 1.04 1.45 1.34 25.52 1.21 1.38 1.03 1.34 25.34 1.19

CV 2.58 0.99 0.69 3.58 10.27 2.02 2.81 0.76 3.53 10.20 2.07

Sample C

Day 1 1.78 1.09 1.70 1.63 38.80 1.47 1.75 1.07 1.63 38.66 1.45

Day 2 1.71 1.08 1.76 1.58 36.82 1.43 1.68 1.06 1.59 36.94 1.41

Day 3 1.69 1.11 1.65 1.53 34.52 1.44 1.64 1.08 1.52 34.08 1.40

mean 1.73 1.09 1.70 1.58 36.71 1.45 1.69 1.07 1.58 36.56 1.42

CV 2.77 1.24 3.11 3.37 5.83 1.55 3.20 1.09 3.61 6.32 1.85

Sample Z

Day 1 1.32 0.99 1.38 1.33 24.69 1.21 1.30 0.98 1.32 24.51 1.19

Day 2 1.36 1.00 1.51 1.36 26.51 1.15 1.33 0.98 1.36 26.65 1.13

Day 3 1.36 1.01 1.47 1.35 26.16 1.15 1.33 0.98 1.35 25.67 1.12

mean 1.35 1.00 1.45 1.35 25.79 1.17 1.32 0.98 1.34 25.61 1.15

CV 1.72 0.64 4.63 1.30 3.75 2.92 1.47 0.36 1.43 4.17 3.22

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.65 1.05 1.62 1.56 35.92 1.62 1.04 1.56 35.77

Day 2 1.53 1.05 1.62 1.46 31.49 1.51 1.03 1.46 31.62

Day 3 1.44 1.05 1.49 1.37 27.24 1.40 1.03 1.37 26.76

mean 1.54 1.05 1.58 1.46 31.55 1.51 1.03 1.46 31.38

CV 6.62 0.28 4.90 6.36 13.74 7.12 0.58 6.56 14.38

WHO/BS/2014.2244

Laboratory 15


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 0.96 1.08 1.10 0.98 -1.55

Day 2 0.94 1.09 1.10 0.98 -1.55

Day 3 0.98 1.12 1.13 0.99 -1.22

mean 0.96 1.10 1.11 0.99 -1.44

CV 2.11 1.73 1.54 0.19 -13.43

Sample A

Day 1 0.92 0.91 0.97 1.02 1.53

Day 2 0.92 0.91 0.95 1.02 1.52

Day 3 0.89 0.88 0.99 1.01 1.20

mean 0.91 0.90 0.97 1.01 1.42

CV 1.71 1.52 1.94 0.19 13.25

Sample B

Day 1 1.35 0.95 1.35 1.42 29.33 1.46 1.05 1.39 28.24

Day 2 1.37 0.95 1.35 1.44 30.42 1.49 1.05 1.42 29.34

Day 3 1.35 0.93 1.41 1.44 30.65 1.50 1.06 1.42 29.80

mean 1.35 0.95 1.37 1.43 30.13 1.48 1.05 1.41 29.13

CV 0.94 1.16 2.59 1.00 2.33 1.52 0.40 1.13 2.76

Sample C

Day 1 1.71 1.00 1.64 1.71 41.55 1.85 1.10 1.68 40.64

Day 2 1.74 1.01 1.62 1.72 41.88 1.89 1.11 1.69 40.98

Day 3 1.68 0.99 1.67 1.70 41.16 1.88 1.12 1.68 40.44

mean 1.71 1.00 1.64 1.71 41.53 1.87 1.11 1.69 40.69

CV 1.50 0.88 1.49 0.62 0.88 1.07 1.05 0.46 0.67

Sample Z

Day 1 1.10 0.95 1.10 1.16 13.44 1.19 1.04 1.14 12.09

Day 2 1.11 0.96 1.09 1.16 13.56 1.20 1.06 1.14 12.22

Day 3 1.10 0.94 1.14 1.16 14.15 1.23 1.07 1.15 13.10

mean 1.10 0.95 1.11 1.16 13.72 1.21 1.06 1.14 12.47

CV 0.54 0.70 2.50 0.44 2.77 1.78 1.19 0.63 4.41

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.56 1.06 1.41 1.47 32.18 1.69 1.16 1.45 31.13

Day 2 1.59 1.06 1.41 1.50 33.19 1.73 1.17 1.47 32.15

Day 3 1.55 1.03 1.47 1.50 33.30 1.73 1.17 1.48 32.49

mean 1.57 1.05 1.43 1.49 32.89 1.72 1.17 1.47 31.92

CV 1.24 1.40 2.48 0.91 1.87 1.35 0.33 1.04 2.22

WHO/BS/2014.2244

Laboratory 16


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.12 1.10 1.05 1.05 4.61

Day 2 1.15 1.04 0.99 1.04 3.96

Day 3 1.19 1.08 1.02 1.06 5.32

mean 1.15 1.07 1.02 1.05 4.63

CV 3.02 3.12 2.73 0.71 14.61

Sample A

Day 1 0.91 0.95 1.07 0.95 -4.84 1.01

Day 2 0.97 1.01 1.10 0.96 -4.13 1.00

Day 3 0.93 0.98 1.12 0.95 -5.62 0.96

mean 0.93 0.98 1.10 0.95 -4.86 0.99

CV 3.16 2.73 2.66 0.71 -15.31 2.95

Sample B

Day 1 1.49 0.99 1.68 1.51 33.61 0.80 1.64 1.04 1.58 36.67

Day 2 1.58 1.07 1.69 1.48 32.25 0.81 1.63 1.06 1.54 34.93

Day 3 1.45 1.02 1.68 1.42 29.45 0.83 1.56 1.04 1.50 33.20

mean 1.50 1.03 1.69 1.47 31.77 0.81 1.61 1.05 1.54 34.93

CV 4.45 3.88 0.38 3.08 6.67 1.76 2.75 1.20 2.67 4.97

Sample C

Day 1 1.88 1.08 1.95 1.74 42.59 0.80 2.06 1.13 1.83 45.24

Day 2 1.97 1.10 2.05 1.78 43.92 0.78 2.04 1.10 1.86 46.14

Day 3 1.85 1.06 2.08 1.75 42.87 0.77 2.00 1.08 1.85 45.91

mean 1.90 1.08 2.02 1.76 43.13 0.78 2.03 1.10 1.84 45.76

CV 3.27 2.16 3.37 1.24 1.62 1.41 1.58 2.22 0.86 1.02

Sample Z

Day 1 1.21 1.02 1.33 1.19 15.72 0.90 1.33 1.07 1.24 19.61

Day 2 1.25 1.06 1.36 1.18 15.35 0.93 1.29 1.05 1.23 18.71

Day 3 1.22 1.03 1.40 1.18 15.08 0.91 1.31 1.06 1.24 19.60

mean 1.23 1.04 1.36 1.18 15.39 0.91 1.31 1.06 1.24 19.31

CV 1.78 1.93 2.64 0.38 2.08 1.36 1.39 0.85 0.64 2.68

Local Negative

Day 1 0.82 1.02 0.89 0.80 -25.00 0.90 1.08 0.84 -19.23

Day 2 0.84 1.07 0.91 0.79 -26.69 0.87 1.06 0.82 -21.67

Day 3 0.79 1.03 0.91 0.77 -30.33 0.85 1.05 0.81 -23.40

mean 0.82 1.04 0.90 0.79 -27.34 0.88 1.06 0.82 -21.43

CV 3.33 2.40 0.94 2.12 -9.95 2.81 1.08 1.73 -9.75

Local Positive

Day 1 2.43 1.26 2.15 1.93 48.07 2.67 1.32 2.02 50.47

Day 2 2.57 1.38 2.14 1.87 46.46 2.66 1.37 1.94 48.58

Day 3 2.36 1.32 2.13 1.80 44.32 2.55 1.35 1.90 47.28

mean 2.45 1.32 2.14 1.86 46.28 2.63 1.35 1.95 48.78

CV 4.37 4.47 0.48 3.49 4.07 2.52 1.74 3.15 3.28

WHO/BS/2014.2244

Laboratory 17


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.17 0.96 0.93 1.03 2.79

Day 2 1.18 1.00 1.16 0.86 -16.49

Day 3 1.25 1.04 0.94 1.11 9.68

mean 1.20 1.00 1.01 1.00 -1.34

CV 3.64 3.89 13.13 12.74 -1011.80

Sample A

Day 1 1.04 0.92 1.13 1.13 11.86

Day 2 1.00 0.73 1.38 1.38 27.53

Day 3 0.97 0.86 1.13 1.13 11.43

mean 1.00 0.83 1.21 1.21 16.94

CV 3.90 11.85 11.79 11.79 54.15

Sample B

Day 1 1.49 0.96 1.55 1.55 35.61 1.43 1.04 1.37 26.95

Day 2 1.45 0.76 1.90 1.90 47.31 1.44 1.05 1.38 27.29

Day 3 1.32 0.90 1.47 1.47 31.88 1.37 1.05 1.30 23.09

mean 1.42 0.87 1.64 1.64 38.27 1.41 1.05 1.35 25.78

CV 6.31 11.68 13.88 13.88 21.03 2.90 0.31 3.09 9.04

Sample C

Day 1 1.85 1.03 1.80 1.80 44.36 1.77 1.12 1.58 36.87

Day 2 1.72 0.80 2.16 2.16 53.71 1.72 1.10 1.57 36.13

Day 3 1.67 1.00 1.66 1.66 39.86 1.73 1.17 1.47 32.10

mean 1.75 0.94 1.87 1.87 45.98 1.74 1.13 1.54 35.03

CV 5.39 13.54 13.74 13.74 15.37 1.70 3.44 3.87 7.32

Sample Z

Day 1 1.33 0.88 1.50 1.50 33.33 1.27 0.96 1.32 24.36

Day 2 1.58 0.75 2.12 2.12 52.80 1.58 1.03 1.54 34.88

Day 3 1.30 0.89 1.47 1.47 32.10 1.35 1.03 1.30 23.34

mean 1.40 0.84 1.70 1.70 39.41 1.40 1.01 1.39 27.53

CV 11.12 9.40 21.53 21.53 29.47 11.56 4.13 9.27 23.20

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.98 1.07 1.85 1.85 46.08 1.90 1.16 1.63 38.82

Day 2 1.44 0.89 1.61 1.61 37.88 1.44 1.23 1.17 14.28

Day 3 2.13 0.95 2.24 2.24 55.29 2.20 1.11 1.98 49.52

mean 1.85 0.97 1.90 1.90 46.42 1.85 1.17 1.59 34.21

CV 19.62 9.12 16.63 16.63 18.77 20.93 5.12 25.64 52.81

WHO/BS/2014.2244

Laboratory 18a


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 0.65 0.99 0.97 1.02 2.02

Day 2 1.33 0.88 0.99 0.89 -12.04

Day 3 0.65 0.94 0.97 0.97 -3.57

mean 0.87 0.94 0.98 0.96 -4.53

CV 44.74 5.89 0.93 6.70 -156.28

Sample A

Day 1 1.01 1.03 0.64 0.98 -2.06 1.01

Day 2 1.14 1.01 1.48 1.12 10.75 1.08

Day 3 1.07 1.03 0.67 1.04 3.45 0.99

mean 1.07 1.03 0.93 1.05 4.04 1.03

CV 5.91 0.93 51.64 6.77 158.90 4.36

Sample B

Day 1 1.30 1.11 0.75 1.16 14.05 1.16 1.28 1.08 1.19 15.79

Day 2 1.50 1.11 1.79 1.35 26.00 1.30 1.32 1.09 1.21 17.10

Day 3 1.30 1.12 0.75 1.15 13.25 1.17 1.21 1.09 1.11 10.15

mean 1.36 1.12 1.10 1.22 17.77 1.21 1.27 1.09 1.17 14.35

CV 8.61 0.64 54.74 9.14 40.20 6.52 4.25 0.59 4.22 25.71

Sample C

Day 1 1.43 1.20 0.77 1.19 15.80 1.24 1.41 1.16 1.21 17.50

Day 2 1.70 1.21 1.87 1.41 29.08 1.46 1.50 1.19 1.26 20.54

Day 3 1.40 1.22 0.74 1.15 12.67 1.22 1.31 1.19 1.11 9.55

mean 1.51 1.21 1.13 1.25 19.18 1.31 1.41 1.18 1.19 15.86

CV 11.05 0.95 57.02 11.41 45.43 10.11 6.59 1.13 6.58 35.78

Sample Z

Day 1 1.16 1.09 0.69 1.06 5.84 1.09 1.15 1.06 1.08 7.74

Day 2 1.36 1.07 1.67 1.26 20.85 1.21 1.19 1.06 1.13 11.32

Day 3 1.19 1.10 0.70 1.08 7.70 1.06 1.12 1.07 1.05 4.41

mean 1.24 1.09 1.02 1.14 11.46 1.12 1.15 1.06 1.09 7.82

CV 8.44 1.34 55.33 9.74 71.37 7.16 3.27 0.53 3.76 44.21

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.59 1.10 0.94 1.44 30.74 1.37 1.57 1.07 1.47 32.14

Day 2 1.56 1.06 1.95 1.47 32.01 1.47 1.37 1.05 1.31 23.83

Day 3 1.63 1.09 0.97 1.49 32.92 1.33 1.52 1.06 1.44 30.52

mean 1.59 1.08 1.28 1.47 31.89 1.39 1.49 1.06 1.41 28.83

CV 2.06 1.95 44.91 1.60 3.43 5.08 7.04 1.08 6.01 15.29

WHO/BS/2014.2244

Laboratory 18b


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 1.10 1.10 1.05 1.05 4.98

Day 2 1.12 1.13 1.07 1.05 4.83

Day 3 1.10 1.09 1.05 1.04 4.08

mean 1.11 1.11 1.06 1.05 4.63

CV 1.12 1.67 1.40 0.51 10.45

Sample A

Day 1 0.91 0.95 1.04 0.95 -5.24 0.92

Day 2 0.89 0.93 1.07 0.95 -5.08 0.92

Day 3 0.92 0.95 1.05 0.96 -4.25 0.95

mean 0.90 0.95 1.05 0.95 -4.85 0.93

CV 1.66 1.39 1.04 0.51 -10.93 1.99

Sample B

Day 1 1.42 0.99 1.58 1.44 30.60 1.27 1.57 1.03 1.52 34.05

Day 2 1.38 0.96 1.61 1.44 30.48 1.23 1.56 1.03 1.51 33.84

Day 3 1.40 0.99 1.56 1.42 29.36 1.26 1.53 1.04 1.48 32.24

mean 1.40 0.98 1.58 1.43 30.15 1.25 1.55 1.04 1.50 33.38

CV 1.38 1.72 1.77 0.97 2.27 1.30 1.13 0.40 1.48 2.97

Sample C

Day 1 1.78 1.03 1.90 1.73 42.26 1.54 1.97 1.08 1.82 45.13

Day 2 1.74 1.02 1.91 1.71 41.44 1.53 1.97 1.10 1.79 44.26

Day 3 1.80 1.05 1.89 1.72 41.74 1.54 1.97 1.10 1.79 44.12

mean 1.77 1.03 1.90 1.72 41.81 1.54 1.97 1.09 1.80 44.50

CV 1.73 1.50 0.71 0.72 1.00 0.17 1.97 1.08 1.82 45.13

Sample Z

Day 1 1.34 0.94 1.56 1.42 29.42 1.17 1.48 0.99 1.49 32.93

Day 2 1.23 0.92 1.50 1.34 25.55 1.12 1.39 0.99 1.41 29.15

Day 3 1.31 0.94 1.53 1.39 28.13 1.14 1.44 0.99 1.45 31.06

mean 1.29 0.94 1.53 1.38 27.70 1.14 1.44 0.99 1.45 31.05

CV 4.30 1.68 1.71 2.70 7.11 2.48 3.04 0.31 2.74 6.09

Local Low

Day 1 1.28 1.06 1.32 1.20 16.99 1.41 1.11 1.27 21.12

Day 2 1.19 1.01 1.31 1.17 14.60 1.34 1.09 1.23 18.72

Day 3 1.25 1.06 1.30 1.19 15.70 1.37 1.11 1.24 19.13

mean 1.24 1.04 1.31 1.19 15.76 1.37 1.10 1.24 19.66

CV 3.73 2.42 0.79 1.43 7.61 2.58 1.08 1.61 6.53

Local Positive

Day 1 1.75 1.06 1.81 1.65 39.45 1.93 1.11 1.74 42.47

Day 2 1.71 1.07 1.79 1.60 37.39 1.94 1.15 1.68 40.41

Day 3 1.73 1.06 1.78 1.62 38.39 1.89 1.11 1.69 40.90

mean 1.73 1.06 1.80 1.62 38.41 1.92 1.13 1.70 41.26

CV 0.91 0.78 0.94 1.68 2.69 1.39 2.14 1.84 2.60

WHO/BS/2014.2244

Laboratory 19


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 1.00 0.95 0.98 0.97 -3.33

Day 2 0.99 1.04

Day 3 0.97 0.96

mean 0.99 0.98

CV 1.79 5.40

Sample A

Day 1 1.05 1.02 1.03 1.03 3.23

Day 2 0.96

Day 3 1.05

mean 1.02 1.02 1.03 1.03 3.23

CV 5.24

Sample B

Day 1 1.42 1.03 1.38 1.38 27.63 1.35 1.01 1.34 25.22

Day 2 1.37 1.03 1.33 1.34 25.17 1.43

Day 3 1.41 1.05 1.30 1.35 25.78 1.35

mean 1.40 1.03 1.34 1.36 26.20 1.38

CV 2.02 0.99 3.08 1.75 4.90 3.41

Sample C

Day 1 1.74 1.06 1.64 1.64 38.93 1.65 1.04 1.58 36.89

Day 2 1.72 1.06 1.61 1.63 38.46 1.80

Day 3 1.71 1.06 1.56 1.61 38.01 1.63

mean 1.72 1.06 1.60 1.63 38.47 1.69

CV 0.91 0.20 2.51 0.75 1.20 5.28

Sample Z

Day 1 1.29 1.01 1.27 1.27 21.49 1.23 0.99 1.23 18.87

Day 2 1.23 0.99 1.23 1.24 19.54 1.29

Day 3 1.27 1.21

mean 1.27 1.00 1.25 1.26 20.52 1.24

CV 2.38 1.59 2.33 1.74 6.73 3.12

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 2.12 1.14 1.86 1.86 46.12 2.01 1.12 1.80 44.33

Day 2 2.18 1.16 1.87 1.88 46.86 2.28

Day 3 2.17 1.15 1.82 1.88 46.94 2.07

mean 2.16 1.15 1.85 1.87 46.64 2.12

CV 1.57 0.85 1.28 0.84 0.97 6.69

APTT

WHO/BS/2014.2244

Laboratory 1


Clotting time ratio Mix ratio Clotting time ratio Mix ratio

PNP

Day 1 0.89

Day 2 0.89

Day 3 0.90

Mean 0.89

CV 0.08

Sample A

Day 1 1.12 1.02

Day 2 1.12 1.03

Day 3 1.12 1.01

Mean 1.12 1.02

CV 0.08 1.08

Sample B

Day 1 1.90 1.53 1.70 1.37

Day 2 1.91 1.54 1.70 1.37

Day 3 1.94 1.59 1.74 1.42

Mean 1.92 1.55 1.71 1.39

CV 1.28 2.24 1.35 2.31

Sample C

Day 1 2.45 1.71 2.19 1.53

Day 2 2.55 1.71 2.28 1.53

Day 3 2.57 1.73 2.30 1.55

Mean 2.52 1.72 2.26 1.54

CV 2.56 0.57 2.58 0.64

Sample Z

Day 1 1.28 1.05 1.14 0.94

Day 2 1.37 1.09 1.22 0.98

Day 3 1.35 1.09 1.21 0.97

Mean 1.33 1.08 1.19 0.96

CV 3.46 2.20 3.45 2.20

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 2.79 2.49

Day 2 2.79 2.49

Day 3 2.76 2.47

Mean 2.78 2.48

CV 0.63 0.56

WHO/BS/2014.2244

Laboratory 4

Day 1 80:20 mix

Samples Clotting times (s)

1 2 Mean

Local normal platelet poor plasma

45.2 46.5 45.9 healthy donor

Number of donors: 1

Reference range: 52 s

A mix test 80/20 43.9 45.3 44.6

B mix test 80/20 60.7 63.8 62.3

C mix test 80/20 65.8 67.8 66.8

Z mix test 80/20 46.7 45.7 46.2

In-house LA positive control 131 120.1 125.6

Day 2 80:20 mix


1 2 Mean


45.4 47.4 46.4 healthy donor

Number of donors: 1


A mix test 80/20 47.4 46.8 47.1

B mix test 80/20 55 58.5 56.8

C mix test 80/20 66.52 71.9 69.1

Z mix test 80/20 47.3 48.3 47.8

In-house LA positive control 111.5 114.7 113.1

Day 3 80:20 mix


1 2 Mean


47 46.8 46.4 healthy donor

Number of donors: 1


A mix test 80/20 43.1 44 43.6

B mix test 80/20 53.2 60.3 56.8

C mix test 80/20 65.4 64.5 65

Z mix test 80/20 47.7 45.3 46.5

In-house LA positive control 121.9 110.7 116.3

WHO/BS/2014.2244

Laboratory 5


Clotting time

ratio Mix ratio

Clotting time

ratio Mix ratio

PNP

Day 1 0.95

Day 2 1.02

Day 3 0.92

Mean 0.96

CV 5.81

Sample A

Day 1 1.05 1.03

Day 2 0.98

Day 3 1.09 1.05

Mean 1.04 1.04

CV 5.70 1.53

Sample B

Day 1 1.46 1.07 1.38 1.01

Day 2 1.52 1.16 1.43 1.10

Day 3 1.40 1.07 1.39 1.07

Mean 1.46 1.10 1.40 1.06

CV 4.18 5.07 1.78 4.14

Sample C

Day 1 1.68 1.29 1.59 1.22

Day 2 1.61 1.25 1.65 1.28

Day 3 1.80 1.42 1.65 1.30

Mean 1.70 1.32 1.63 1.27

CV 5.75 6.92 2.02 3.37

Sample Z

Day 1 1.20 0.99 1.21 0.96

Day 2 1.28 1.06 1.23 1.01

Day 3 1.25 1.02 1.17 0.97

Mean 1.20 0.99 1.20 0.98

CV 3.35 3.65 2.51 2.55

Local Negative

Day 1 1.00 0.94

Day 2 0.96 0.98

Day 3 1.04 0.95

Mean 1.00 0.96

CV 4.43 1.87

Local Positive

Day 1 1.55 1.47

Day 2 1.46 1.50

Day 3 1.60 1.46

Mean 1.54 1.48

CV 4.50 1.25

WHO/BS/2014.2244

Laboratory 6

Against Laboratory PNP Against A

Screen

ratio

Confirm

ratio Screen/confirm NR

Mix

ratio

CT

ratio

Confirm

ratio NR

Mix

ratio

PNP

Day 1 0.81 0.88 1.10 0.80

Day 2 0.80 0.84 0.98 0.86

Day 3 0.83 0.87 0.97 0.89

Mean 0.81 0.87 1.02 0.85

CV 1.74 2.40 7.07 5.45

Sample A

Day 1 1.13 0.91 1.01 1.25

Day 2 1.19 1.02 0.93 1.16

Day 3 1.15 1.03 0.93 1.12

Mean 1.16 0.99 0.96 1.18

CV 2.42 6.80 4.94 5.54

Sample B

Day 1 1.44 1.24 0.95 1.17 1.27 1.36 0.93

Day 2 1.73 1.20 1.16 1.44 1.70 1.46 1.18 1.24 1.43

Day 3 1.71 1.19 1.19 1.44 1.72 1.49 1.16 1.28 1.49

Mean 1.63 1.21 1.10 1.35 1.71 1.41 1.23 1.15 1.46

CV 9.96 2.02 12.13 11.75 0.61 8.32 9.14 16.53 2.92

Sample C

Day 1 2.09 1.27 1.34 1.65 1.84 1.39 1.32

Day 2 2.11 1.32 1.28 1.60 1.74 1.78 1.29 1.38 1.47

Day 3 2.09 1.23 1.41 1.70 1.67 1.82 1.20 1.52 1.45

Mean 2.10 1.27 1.34 1.65 1.71 1.81 1.29 1.41 1.46

CV 0.76 3.65 4.69 2.96 3.05 1.70 7.59 7.16 0.74

Sample Z

Day 1 1.53 1.29 0.96 1.19 1.35 1.42 0.95

Day 2 1.63 1.32 0.99 1.23 1.35 1.37 1.29 1.06 1.14

Day 3 1.52 1.23 1.03 1.24 1.27 1.32 1.20 1.11 1.11

Mean 1.56 1.28 0.99 1.22 1.31 1.35 1.30 1.04 1.12

CV 3.89 3.71 3.09 2.20 4.06 1.95 8.65 7.51 1.75

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.57 1.28 1.17 1.23 1.39 1.20 1.15

Day 2 1.71 1.37 1.15 1.25 1.44 1.17 1.23

Day 3 1.65 1.37 1.21 1.21 1.43 1.10 1.30

Mean 1.64 1.34 1.17 1.23 1.42 1.16 1.23

CV 4.16 4.01 2.52 1.73 1.98 4.37 5.96

WHO/BS/2014.2244

Laboratory 7


Clotting time

ratio Mix ratio

Clotting time

ratio Mix ratio

PNP

Day 1 0.83

Day 2 0.83

Day 3 0.86

Mean 0.84

CV 1.82

Sample A

Day 1 1.20 1.09

Day 2 1.20 1.10

Day 3 1.17 1.09

Mean 1.19 1.09

CV 1.80 0.55

Sample B

Day 1 1.64 1.28 1.36 1.06

Day 2 1.63 1.31 1.36 1.09

Day 3 1.66 1.30 1.42 1.12

Mean 1.64 1.30 1.38 1.09

CV 0.84 1.33 2.61 2.63

Sample C

Day 1 2.10 1.50 1.74 1.24

Day 2 2.15 1.54 1.79 1.28

Day 3 2.23 1.58 1.91 1.35

Mean 2.16 1.54 1.81 1.29

CV 3.01 2.60 4.80 4.26

Sample Z

Day 1 1.27 1.13 1.06 0.93

Day 2 1.27 1.14 1.06 0.95

Day 3 1.31 1.15 1.12 0.98

Mean 1.28 1.14 1.08 0.95

CV 1.52 0.87 3.36 2.61

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 3.39 2.82

Day 2 3.69 3.07

Day 3 3.76 3.23

Mean 3.62 3.04

CV 5.40 6.78

WHO/BS/2014.2244

Laboratory 8a


Screen ratio -

PTT (8a1)

Screen ratio –

Pathromtin

(8a2)

Screen ratio -

PTT (8a1)

Screen ratio –

Pathromtin

(8a2)

PNP

Day 1 0.92 0.92

Day 2 0.91 0.92

Day 3 0.92 0.92

Mean 0.92 0.92

CV 0.42 0.33

Sample A

Day 1 1.09 1.09

Day 2 1.10 1.08

Day 3 1.09 1.08

Mean 1.09 1.09

CV 0.42 0.34

Sample B

Day 1 1.36 1.22 1.25 1.12

Day 2 1.35 1.22 1.23 1.12

Day 3 1.36 1.20 1.25 1.11

Mean 1.36 1.21 1.24 1.12

CV 0.32 0.62 0.74 0.53

Sample C

Day 1 1.66 1.31 1.53 1.21

Day 2 1.58 1.35 1.44 1.24

Day 3 1.63 1.32 1.49 1.22

Mean 1.62 1.33 1.49 1.22

CV 2.55 1.25 2.97 1.47

Sample Z

Day 1 1.24 1.29 1.14 1.18

Day 2 1.20 1.28 1.09 1.18

Day 3 1.22 1.27 1.12 1.18

Mean 1.22 1.28 1.12 1.18

CV 1.84 0.66 2.26 0.34

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.86 1.51 1.71 1.38

Day 2 2.00 1.51 1.82 1.40

Day 3 1.99 1.50 1.82 1.39

Mean 1.95 1.51 1.78 1.39

CV 4.12 0.36 3.77 0.50

WHO/BS/2014.2244

Laboratory 8b


Screen ratio -

PTT (8b1)

Screen ratio –

Pathromtin

(8b2)

Screen ratio -

PTT (8b1)

Screen ratio –

Pathromtin

(8b2)

PNP

Day 1 0.90 0.90

Day 2 0.89 0.90

Day 3 0.89 0.90

Mean 0.89 0.90

CV 0.20 0.19

Sample A

Day 1 1.11 1.11

Day 2 1.12 1.11

Day 3 1.12 1.12

Mean 1.12 1.11

CV 0.20 0.19

Sample B

Day 1 1.33 1.23 1.19 1.10

Day 2 1.33 1.25 1.19 1.12

Day 3 1.32 1.25 1.18 1.12

Mean 1.33 1.24 1.19 1.11

CV 0.24 0.82 0.43 0.71

Sample C

Day 1 1.53 1.34 1.37 1.21

Day 2 1.47 1.39 1.31 1.25

Day 3 1.52 1.38 1.36 1.23

Mean 1.51 1.37 1.35 1.23

CV 2.03 1.88 2.14 1.83

Sample Z

Day 1 1.20 1.35 1.08 1.21

Day 2 1.19 1.34 1.07 1.20

Day 3 1.19 1.35 1.06 1.21

Mean 1.19 1.34 1.07 1.21

CV 0.45 0.30 0.65 0.32

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.80 1.53 1.61 1.38

Day 2 1.80 1.56 1.61 1.40

Day 3 1.80 1.56 1.61 1.40

Mean 1.80 1.55 1.61 1.39

CV 0.10 0.97 0.17 0.86

WHO/BS/2014.2244

Laboratory 8c


Screen ratio -

PTT (8c1)

Screen ratio –

Pathromtin

(8c2)

Screen ratio -

PTT (8c1)

Screen ratio –

Pathromtin

(8c2)

PNP

Day 1 0.88 0.90

Day 2 0.89 0.90

Day 3 0.89 0.90

Mean 0.89 0.90

CV 0.76 0.46

Sample A

Day 1 1.13 1.12

Day 2 1.12 1.11

Day 3 1.12 1.12

Mean 1.12 1.11

CV 0.76 0.46

Sample B

Day 1 1.38 1.24 1.21 1.11

Day 2 1.32 1.24 1.18 1.12

Day 3 1.34 1.23 1.19 1.10

Mean 1.35 1.24 1.20 1.11

CV 2.08 0.18 1.31 0.59

Sample C

Day 1 1.60 1.36 1.41 1.22

Day 2 1.50 1.41 1.34 1.27

Day 3 1.54 1.38 1.37 1.23

Mean 1.55 1.38 1.37 1.24

CV 3.19 1.85 2.44 2.26

Sample Z

Day 1 1.21 1.34 1.07 1.20

Day 2 1.20 1.34 1.08 1.21

Day 3 1.21 1.35 1.08 1.21

Mean 1.21 1.35 1.08 1.21

CV 0.56 0.49 0.56 0.37

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.84 1.55 1.63 1.39

Day 2 1.80 1.57 1.61 1.42

Day 3 1.83 1.56 1.63 1.40

Mean 1.83 1.56 1.62 1.40

CV 1.23 0.74 0.72 1.07

WHO/BS/2014.2244

Laboratory 9


Screen

ratio

Mix ratio

50:50

Mix ratio

80:20

Screen

ratio

Mix ratio

50:50

Mix ratio

80:20

PNP

Day 1 0.97

Day 2 0.96

Day 3 0.97

Mean 0.96

CV 0.97

Sample A

Day 1 1.03 1.00 1.02

Day 2 1.04 1.01 1.03

Day 3 1.03 1.00 1.02

Mean 1.03 1.00 1.02

CV 0.35 0.48 0.82

Sample B

Day 1 1.56 1.10 1.39 1.51 1.07 1.35

Day 2 1.56 1.12 1.41 1.51 1.08 1.35

Day 3 1.56 1.11 1.37 1.51 1.08 1.32

Mean 1.56 1.11 1.39 1.51 1.08 1.34

CV 0.22 0.64 1.43 0.21 0.47 1.21

Sample C

Day 1 1.88 1.55 1.76 1.83 1.50 1.71

Day 2 1.92 1.54 1.76 1.85 1.48 1.70

Day 3 1.86 1.54 1.79 1.81 1.50 1.73

Mean 1.89 1.55 1.77 1.83 1.49 1.71

CV 1.46 0.30 0.91 1.15 0.62 1.11

Sample Z

Day 1 1.22 1.07 1.14 1.18 1.03 1.11

Day 2 1.23 1.08 1.15 1.18 1.04 1.11

Day 3 1.24 1.07 1.07 1.20 1.03 1.03

Mean 1.23 1.07 1.12 1.19 1.03 1.08

CV 1.02 0.51 4.05 1.09 0.16 3.88

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.37 1.33

Day 2 1.39 1.34

Day 3 1.14 1.10

Mean 1.30 1.26

CV 10.89 10.72

WHO/BS/2014.2244

Laboratory 10


Clotting time

ratio Mix ratio

Clotting time

ratio Mix ratio

PNP

Day 1 1.02

Day 2 1.04

Day 3 1.04

Mean 1.03

CV 0.88

Sample A

Day 1 0.98 0.91

Day 2 0.96 0.90

Day 3 0.96 0.85

Mean 0.97 0.89

CV 0.89 3.37

Sample B

Day 1 1.25 1.27 1.27 1.29

Day 2 1.24 1.26 1.29 1.30

Day 3 1.29 1.24 1.34 1.29

Mean 1.26 1.25 1.30 1.29

CV 1.87 1.10 2.42 0.70

Sample C

Day 1 1.54 1.24 1.58 1.26

Day 2 1.61 1.26 1.67 1.30

Day 3 1.59 1.24 1.65 1.29

Mean 1.58 1.24 1.63 1.28

CV 2.21 0.92 3.06 1.60

Sample Z

Day 1 1.17 1.00 1.20 1.02

Day 2 1.17 1.00 1.21 1.04

Day 3 1.27 1.01 1.32 1.05

Mean 1.20 1.01 1.24 1.04

CV 4.83 0.52 5.34 1.24

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 2.90 2.02 2.96 2.06

Day 2 2.70 1.94 2.80 2.01

Day 3 2.69 1.85 2.80 1.92

Mean 2.76 1.94 2.85 2.00

CV 4.29 4.14 3.38 3.39

WHO/BS/2014.2244

Laboratory 11a


Clotting time

ratio Mix ratio

Clotting time

ratio Mix ratio

PNP

Day 1 0.85 0.85

Day 2 0.85 0.85

Day 3 0.89 0.86

Mean 0.86 0.85

CV 2.61 0.54

Sample A

Day 1 1.17 1.07

Day 2 1.18 1.08

Day 3 1.12 1.03

Mean 1.16 1.06

CV 2.58 2.37

Sample B

Day 1 1.70 1.48 1.45 1.26

Day 2 1.66 1.46 1.41 1.24

Day 3 1.70 1.48 1.51 1.32

Mean 1.68 1.47 1.46 1.27

CV 1.42 0.85 3.67 3.26

Sample C

Day 1 2.10 1.62 1.79 1.39

Day 2 2.03 1.56 1.73 1.32

Day 3 2.16 1.66 1.92 1.48

Mean 2.10 1.61 1.81 1.40

CV 2.94 3.18 5.47 5.61

Sample Z

Day 1 1.45 1.22 1.24 1.04

Day 2 1.46 1.22 1.24 1.04

Day 3 1.52 1.26 1.35 1.12

Mean 1.48 1.23 1.28 1.07

CV 2.49 1.70 5.08 4.32

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.66 1.45 1.42 1.24

Day 2 1.59 1.41 1.35 1.20

Day 3 1.68 1.45 1.49 1.29

Mean 1.64 1.44 1.42 1.24

CV 2.96 1.73 5.21 3.88

WHO/BS/2014.2244

Laboratory 11b

Only mix results were returned therefore the results were unable to be analysed in the same

manner as the other APTT results.

Day 1


1 2 Mean


60.3 58 59.2

A mix 63.8 63.7 63.8

B mix 94.7 93.2 94

C mix 107.4 105.2 106.3

Z mix 77.2 76.6 76.9

Positive control 101.7 99.9 100.8

Day 1 + phospholipid


1 2 Mean


60.8 60.7 60.8

A mix 60.6 59.9 60.3

B mix 78.5 78.2 78.4

C mix 82.7 82.1 82.4

Z mix 70.6 70.1 70.4

Positive control 79.6 78.3 79

Day 2


1 2 Mean


54.4 52.3 53.4

A mix 60.1 61.4 60.8

B mix 87.6 81.9 84.8

C mix 94.7 96.9 95.8

Z mix 70.9 74.7 72.8


WHO/BS/2014.2244



1 2 Mean


58 56.2 57.1

A mix 60.2 59.9 60.1

B mix 76.6 74.7 75.6

C mix 79 77.4 78.2

Z mix 70.8 70.8 70.8


Day 3


1 2 Mean


52.4 52.8 52.6

A mix 57.3 57.3 57.3

B mix 77.9 77.7 77.8

C mix 90.3 85.3 87.8

Z mix 71.3 67.8 70




1 2 Mean


52.6 55.1 53.9

A mix 53.7 56.1 54.9

B mix 69.6 68.4 69

C mix 73.7 71.4 72.6

Z mix 66.5 61.5 64


WHO/BS/2014.2244

Laboratory 15


Clotting time

ratio – Cephen 5

LR (15a)

Clotting time

ratio – APTT LS

(15b)

Clotting time

ratio – Cephen 5

LR (15a)

Clotting time

ratio – APTT LS

(15b)

PNP

Day 1 1.06 0.98

Day 2 1.06 0.98

Day 3 1.05 0.97

Mean 1.06 0.98

CV 0.65 0.51

Sample A

Day 1 0.95 1.02

Day 2 0.94 1.02

Day 3 0.95 1.03

Mean 0.95 1.02

CV 0.65 0.51

Sample B

Day 1 1.01 1.24 1.07 1.22

Day 2 1.00 1.24 1.06 1.21

Day 3 1.02 1.28 1.07 1.25

Mean 1.01 1.25 1.07 1.22

CV 1.25 2.02 0.61 1.56

Sample C

Day 1 1.08 1.54 1.15 1.51

Day 2 1.07 1.52 1.13 1.49

Day 3 1.07 1.59 1.12 1.55

Mean 1.07 1.55 1.13 1.52

CV 0.99 2.32 1.22 1.91

Sample Z

Day 1 1.08 1.24 1.14 1.21

Day 2 1.06 1.23 1.13 1.20

Day 3 1.04 1.24 1.10 1.21

Mean 1.06 1.24 1.12 1.21

CV 1.75 0.74 2.18 0.58

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.05 1.38 1.11 1.35

Day 2 1.03 1.35 1.10 1.32

Day 3 1.01 1.38 1.07 1.34

Mean 1.03 1.37 1.09 1.34

CV 1.66 0.97 2.08 0.91

WHO/BS/2014.2244

Laboratory 17 – LA test (modified APTT)

Day 1

1 2 Mean LCA index

Neg Sample 91.5 90.2 90.9

-1.35 Sample + Neg 87.5 91.8 89.7

Neg 87.2 90.6 88.9

A Sample 91 87.7 89.4

-9.04 Sample + Neg 83.1 81.3 82.2

Neg 80.1 78 79.1

B Sample 90.2 88.8 89.5

19.95 Sample + Neg 115.5 115.4 115.5

Neg 130.7 129.5 130.1

C Sample 88.9 89.8 89.4

34.1 Sample + Neg 147.8 142.2 145

Neg 166.1 160.3 163.2

Z Sample 87.8 90.2 89

15.03 Sample + Neg 108.2 105.5 106.9

Neg 121 116.5 118.8

Pos Sample 93.3 89.4 91.4

31.42 Sample + Neg 202.7 193.4 198.1

Neg 336.1 343.1 339.6

Day 2

1 2 Mean LCA index

Neg Sample 93.3 98.5 95.9

-2.44 Sample + Neg 89.1 97.3 93.2

Neg 123.4 97.5 110.5

A Sample 90.8 91.3 91.1

-8.61 Sample + Neg 82.2 85.8 84

Neg 79.3 84.5 81.9

B Sample 90.9 89.8 90.4

21.27 Sample + Neg 118 120.4 119.2

Neg 134.3 137 135.7

C Sample 102 101.8 101.9

31.89 Sample + Neg 163.7 158.6 161.2

Neg 189.2 182.4 185.8

Z Sample 90.2 88.5 89.4

15.42 Sample + Neg 110.9 105.4 108.2

Neg 122.1 121.7 121.9

Pos Sample 95.8 102.9 99.4

30.18 Sample + Neg 216.3 216.9 216.6

Neg 401 376.1 388.6

WHO/BS/2014.2244

Day 3

1 2 Mean LCA index

Neg Sample 92.5 88 90.3

-1.64 Sample + Neg 90.8 86.8 88.8

Neg 90.6 86.7 88.7

A Sample 90.9 88.3 89.6

-11.86 Sample + Neg 83.1 78.1 80.6

Neg 78.9 72.9 75.9

B Sample 91.2 87.7 89.5

20.46 Sample + Neg 118.8 114.7 116.8

Neg 141.4 125.4 133.4

C Sample 86.3 87.8 87.1

30.85 Sample + Neg 135.3 139.7 137.5

Neg 170.9 156.2 163.6

Z Sample 88.6 87.2 87.9

15.43 Sample + Neg 105.1 105.9 105.5

Neg 112.5 115.7 114.1

Pos Sample 90.2 88.5 89.4

32.73 Sample + Neg 198.8 188 193.4

Neg 321.4 314.4 317.9

WHO/BS/2014.2244

Laboratory 18


Clotting time

ratio Mix ratio

Clotting time

ratio Mix ratio

PNP

Day 1 0.98

Day 2 1.03

Day 3 0.98

Mean 1.00

CV 3.04

Sample A

Day 1 1.02 0.99

Day 2 0.97 0.94

Day 3 1.02 0.98

Mean 1.00 0.97

CV 2.99 2.69

Sample B

Day 1 1.23 1.10 1.21 1.08

Day 2 1.16 1.05 1.20 1.09

Day 3 1.21 1.12 1.19 1.10

Mean 1.20 1.09 1.20 1.09

CV 3.02 3.23 0.67 0.90

Sample C

Day 1 1.44 1.22 1.42 1.19

Day 2 1.34 1.15 1.38 1.19

Day 3 1.42 1.22 1.39 1.20

Mean 1.40 1.20 1.40 1.20

CV 4.00 3.24 1.29 0.37

Sample Z

Day 1 1.14 1.08 1.12 1.06

Day 2 1.09 1.04 1.12 1.07

Day 3 1.15 1.09 1.13 1.07

Mean 1.12 1.07 1.12 1.07

CV 2.99 2.36 0.58 0.86

Local Low

Day 1 1.28 1.25

Day 2 1.19 1.23

Day 3 1.27 1.24

Mean 1.24 1.24

CV 3.93 1.00

Local Positive

Day 1 1.49 1.46

Day 2 1.38 1.43

Day 3 1.49 1.47

Mean 1.45 1.45

CV 4.48 1.52

WHO/BS/2014.2244

Laboratory 19

Against laboratory PNP

Clotting time ratio –

Actin FS (19a)

Clotting time ratio

– PTT LA (19b)

PNP

Day 1

Day 2

Day 3

Mean

CV

Sample A

Day 1 1.07 1.05

Day 2 1.10

Day 3 1.07 1.09

Mean 1.07 1.08

CV - 2.35

Sample B

Day 1 1.10 1.50

Day 2 1.09 1.50

Day 3 1.10 1.46

Mean 1.10 1.49

CV 1.00 1.31

Sample C

Day 1 1.12 1.64

Day 2 1.12 1.62

Day 3 1.12 1.63

Mean 1.12 1.63

CV 0.02 0.60

Sample Z

Day 1 1.10 1.23

Day 2 1.12 1.25

Day 3 1.10 1.23

Mean 1.11 1.24

CV 0.56 0.80

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 1.14 1.56

Day 2 1.18 1.62

Day 3 1.14 1.65

Mean 1.15 1.61

CV 2.21 2.54

WHO/BS/2014.2244

SCT

Laboratory 2

Against Laboratory PNP Against A

Screen

ratio

Confirm

ratio

Screen/

confirm NR

Correction

ratio

Screen

ratio

Confirm

ratio NR

Correction

ratio

Sample A

Day 1 0.93 0.94 1.01 0.99 -1.28

Day 2 0.87 0.91 0.93 0.95 -18.64

Day 3 0.88 0.87 0.92 1.01 -10.83

Mean 0.89 0.91 0.95 0.98 -10.25

CV 0.04 0.04 0.05 0.03 -0.85

Sample B

Day 1 1.60 0.91 1.63 1.75 102.81 1.80 1.04 1.73 122.08

Day 2 1.57 0.98 1.57 1.61 94.47 1.81 1.07 1.69 121.67

Day 3 1.58 0.89 1.60 1.76 100.92 1.79 1.03 1.74 121.85

Mean 1.58 0.93 1.60 1.71 99.40 1.80 1.05 1.72 121.87

CV 0.01 0.05 0.02 0.05 0.04 0.00 0.02 0.02 0.00

Sample C

Day 1 1.99 0.99 1.87 2.01 149.45 2.24 1.12 1.99 173.68

Day 2 2.03 1.04 1.90 1.94 151.30 2.34 1.14 2.05 185.00

Day 3 2.03 0.96 1.92 2.12 155.91 2.31 1.10 2.09 183.22

Mean 2.02 1.00 1.90 2.02 152.22 2.30 1.12 2.04 180.63

CV 0.01 0.04 0.01 0.04 0.02 0.02 0.02 0.02 0.03

Sample Z

Day 1 1.44 0.93 1.45 1.56 79.82 1.62 1.05 1.54 97.05

Day 2 1.46 1.02 1.41 1.44 76.98 1.69 1.11 1.52 102.94

Day 3 1.43 0.95 1.38 1.51 77.38 1.63 1.09 1.49 96.25

Mean 1.45 0.96 1.41 1.50 78.06 1.65 1.09 1.52 98.75

CV 0.01 0.05 0.03 0.04 0.02 0.02 0.03 0.01 0.04

Local Negative

Day 1 0.93 1.12 1.14 0.99 11.37

Day 2 0.98 1.15 1.09 1.05 20.41

Day 3 0.91 1.14 1.15 0.99 12.48

Mean 0.94 1.14 1.13 1.01 14.75

CV 0.04 0.01 0.03 0.04 0.33

Local Positive

Day 1 1.43 1.01 1.33 1.42 73.26 1.61 1.15 1.41 90.35

Day 2 1.41 1.02 1.34 1.37 67.91 1.62 1.12 1.45 93.18

Day 3 1.42 0.97 1.32 1.46 72.91 1.61 1.12 1.44 91.49

Mean 1.42 1.00 1.33 1.42 71.36 1.62 1.13 1.43 91.68

CV 0.01 0.03 0.01 0.03 0.04 0.00 0.01 0.01 0.02

WHO/BS/2014.2244

Laboratory 5


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 0.94 0.97 0.87 1.11 9.80

Day 2 0.96 0.97 0.85 1.13 11.44

Day 3 0.96 0.98 0.87 1.13 11.72

mean 0.96 0.97 0.86 1.12 10.99

CV 1.08 0.92 0.94 1.16 9.44

Sample A

Day 1 1.04 1.15 0.85 0.90 -10.86 1.00

Day 2 1.04 1.17 0.85 0.89 -12.92

Day 3 1.02 1.16 0.85 0.88 -13.27 0.98

mean 1.03 1.16 0.85 0.89 -12.35 0.99

CV 0.91 0.94 0.18 1.17 -10.54 1.64

Sample B

Day 1 2.10 1.23 1.61 1.71 41.52 1.65 2.03 1.07 1.90 47.25 1.59

Day 2 2.02 1.22 1.60 1.66 39.84 1.60 1.95 1.04 1.88 46.72 1.54

Day 3 1.97 1.23 1.53 1.59 37.26 1.57 1.93 1.07 1.81 44.61 1.54

mean 2.03 1.23 1.58 1.66 39.54 1.61 1.97 1.06 1.86 46.19 1.56

CV 3.33 0.72 2.73 3.52 5.42 2.53 2.64 1.58 2.56 3.02 1.90

Sample C

Day 1 2.69 1.28 1.98 2.10 52.38 2.01 2.59 1.11 2.33 57.05 1.94

Day 2 2.59 1.30 1.93 2.00 50.07 1.96 2.50 1.11 2.26 55.78 1.89

Day 3 2.49 1.28 1.87 1.94 48.46 1.93 2.44 1.11 2.20 54.50 1.90

mean 2.59 1.29 1.93 2.01 50.30 1.97 2.51 1.11 2.26 55.78 1.91

CV 3.84 0.70 3.02 4.00 3.92 1.95 3.06 0.26 2.88 2.28 1.37

Sample Z

Day 1 1.74 1.23 1.33 1.41 29.09 1.22 1.68 1.07 1.56 36.04 1.18

Day 2 1.66 1.23 1.30 1.35 26.08 1.18 1.61 1.05 1.53 34.54 1.14

Day 3 1.69 1.26 1.29 1.34 25.18 1.19 1.65 1.09 1.51 33.94 1.17

mean 1.70 1.24 1.31 1.37 26.78 1.20 1.65 1.07 1.53 34.84 1.16

CV 2.23 1.48 1.78 2.84 7.65 1.69 2.22 1.96 1.67 3.10 1.77

Local Negative

Day 1 1.06 1.07 0.94 0.99 -0.84 1.03 0.93 1.10 9.04

Day 2 1.03 1.08 0.92 0.95 -4.75 1.00 0.92 1.08 7.23

Day 3 1.05 1.08 0.93 0.97 -3.16 1.03 0.93 1.10 8.93

mean 1.05 1.08 0.93 0.97 -2.92 1.02 0.93 1.09 8.40

CV 1.42 0.51 1.01 1.92 -67.46 1.63 0.55 1.10 12.04

Local Positive

Day 1 2.26 1.12 1.90 2.01 50.25 2.18 0.98 2.23 55.13

Day 2 2.17 1.15 1.82 1.89 47.04 2.10 0.98 2.13 53.10

Day 3 2.14 1.14 1.82 1.89 47.03 2.10 0.98 2.14 53.24

mean 2.19 1.14 1.84 1.93 48.11 2.13 0.98 2.17 53.82

CV 2.71 1.19 2.55 3.65 3.86 2.17 0.31 2.49 2.10

WHO/BS/2014.2244

Laboratory 13


Screen ratio Screen/

Confirm

ratio

Mix ratio Screen ratio Mix ratio

PNP

Day 1 0.99

Day 2 0.98

Day 3 1.02

Mean 1.00

CV 1.85

Sample A

Day 1 1.01

Day 2 1.02

Day 3 0.98

Mean 1.00

CV 1.84

Sample B

Day 1 2.00 1.52 1.99 1.51

Day 2 1.86 1.84 1.53 1.83 1.51

Day 3 1.98 1.95 1.52 2.02 1.55

Mean 1.95 1.52 1.95 1.52

CV 3.81 0.58 5.21 1.45

Sample C

Day 1 2.47 2.25 1.88 2.46 1.87

Day 2 2.39 2.19 1.74 2.35 1.71

Day 3 2.42 2.18 1.82 2.46 1.85

Mean 2.43 2.21 1.81 2.42 1.81

CV 1.57 1.69 3.82 2.55 4.84

Sample Z

Day 1 1.61 1.23 1.61 1.23

Day 2 1.63 1.59 1.24 1.60 1.22

Day 3 1.68 1.58 1.22 1.71 1.24

Mean 1.64 1.23 1.64 1.23

CV 2.09 0.95 3.80 0.90

Local Negative

Day 1

Day 2

Day 3

Mean

CV

Local Positive

Day 1 4.84 3.26 4.82

Day 2 5.85 3.26 5.75

Day 3 6.30 3.10 6.42

Mean 5.67 3.21 5.66

CV 13.20 2.96 14.21

WHO/BS/2014.2244

Laboratory 14


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix

ratio

PNP

Day 1 0.95 1.07 0.99 1.08 7.15

Day 2 0.98 1.07 0.97 1.10 9.17

Day 3 0.96 1.07 1.00 1.07 6.38

mean 0.96 1.07 0.99 1.08 7.57

CV 1.30 0.21 1.41 1.57 19.02

Sample A

Day 1 0.94 1.01 0.89 0.93 -7.71 0.95

Day 2 0.93 1.03 0.89 0.91 -10.10 0.95

Day 3 0.94 1.00 0.90 0.94 -6.82 0.96

mean 0.94 1.01 0.89 0.92 -8.21 0.95

CV 0.21 1.42 0.61 1.56 -20.67 0.66

Sample B

Day 1 1.75 1.05 1.59 1.67 40.08 1.53 1.87 1.04 1.80 44.37 1.63

Day 2 1.68 1.08 1.52 1.56 35.85 1.50 1.80 1.05 1.72 41.73 1.60

Day 3 1.66 1.04 1.53 1.60 37.49 1.52 1.78 1.04 1.71 41.48 1.63

mean 1.70 1.06 1.55 1.61 37.81 1.52 1.82 1.04 1.74 42.53 1.62

CV 2.79 1.92 2.44 3.46 5.64 1.09 2.64 0.52 2.83 3.76 0.89

Sample C

Day 1 2.36 1.11 2.03 2.12 52.91 1.88 2.52 1.10 2.29 56.28 2.00

Day 2 2.09 1.22 1.68 1.72 41.79 1.83 2.24 1.18 1.89 47.13 1.96

Day 3 2.15 1.13 1.82 1.91 47.54 1.83 2.30 1.13 2.04 50.89 1.95

mean 2.20 1.15 1.84 1.92 47.41 1.84 2.35 1.14 2.07 51.43 1.97

CV 6.56 4.87 9.47 10.6

0 11.73 1.59 6.35 3.65 9.67 8.95 1.42

Sample Z

Day 1 1.51 1.08 1.33 1.39 28.30 1.24 1.61 1.07 1.50 33.43 1.32

Day 2 1.47 1.09 1.32 1.35 25.99 1.20 1.57 1.06 1.49 32.78 1.29

Day 3 1.49 1.06 1.35 1.41 29.22 1.25 1.59 1.06 1.51 33.74 1.33

mean 1.49 1.08 1.33 1.39 27.84 1.23 1.59 1.06 1.50 33.32 1.32

CV 1.34 1.58 1.22 2.29 5.98 1.97 1.13 0.79 0.73 1.47 1.80

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.92 1.12 1.63 1.71 41.38 2.04 1.11 1.84 45.57

Day 2 1.80 1.10 1.60 1.64 38.99 1.93 1.07 1.80 44.58

Day 3 1.82 1.14 1.53 1.60 37.34 1.94 1.14 1.70 41.34

mean 1.85 1.12 1.58 1.65 39.23 1.97 1.11 1.78 43.83

CV 3.39 1.89 3.28 3.37 5.18 3.20 3.29 3.88 5.06

WHO/BS/2014.2244

dPT

Laboratory 16


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix/

screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

PNP

Day 1 0.86 1.01 1.02 0.99 -0.53

Day 2 0.95 0.97 1.01 0.96 -4.66

Day 3 0.92 0.99 1.05 0.94 -5.90

mean 0.91 0.99 1.03 0.96 -3.70

CV 4.80 2.37 1.87 2.75 -76.10

Sample A

Day 1 0.99 0.98 0.87 1.01 0.53 0.99

Day 2 1.03 0.99 0.99 1.05 4.45 0.96

Day 3 1.01 0.95 0.97 1.06 5.58 0.96

mean 1.01 0.97 0.94 1.04 3.52 0.97

CV 2.36 1.85 7.16 2.71 75.36 1.49

Sample B

Day 1 1.17 1.08 0.93 1.08 7.15 0.88 1.18 1.10 1.07 6.66

Day 2 1.35 1.12 1.14 1.21 17.11 0.81 1.31 1.13 1.15 13.25

Day 3 1.28 1.09 1.08 1.17 14.71 0.84 1.26 1.14 1.11 9.68

mean 1.26 1.10 1.05 1.15 12.99 0.85 1.25 1.13 1.11 9.86

CV 7.29 1.76 10.49 5.83 40.04 4.33 4.97 1.69 3.68 33.49

Sample C

Day 1 1.48 1.15 1.10 1.28 22.00 0.77 1.50 1.17 1.28 21.59

Day 2 1.90 1.24 1.45 1.53 34.72 0.69 1.84 1.26 1.46 31.68

Day 3 1.84 1.22 1.38 1.51 33.58 0.69 1.82 1.28 1.42 29.66

mean 1.74 1.20 1.31 1.44 30.10 0.72 1.72 1.24 1.39 27.64

CV 13.21 3.92 13.98 9.54 23.39 6.55 11.19 4.51 7.13 19.33

Sample Z

Day 1 0.99 0.96 0.88 1.03 2.44 0.99 1.00 0.98 1.02 1.93

Day 2 1.04 0.97 1.01 1.07 6.52 0.96 1.00 0.98 1.02 2.17

Day 3 1.02 0.95 0.99 1.07 6.76 0.96 1.01 1.00 1.01 1.26

mean 1.02 0.96 0.96 1.06 5.24 0.97 1.01 0.99 1.02 1.79

CV 2.56 0.78 7.13 2.52 46.29 1.98 0.67 1.13 0.48 26.58

Local Negative

Day 1 0.93 0.87 0.92 1.07 6.35 0.95 0.89 1.06 5.86

Day 2 0.88 0.91 0.92 0.97 -3.41 0.85 0.92 0.92 -8.22

Day 3 0.87 0.90 0.89 0.97 -3.40 0.86 0.94 0.91 -9.51

mean 0.89 0.89 0.91 1.00 -0.15 0.89 0.92 0.97 -3.96

CV 3.76 2.22 1.91 5.81 -3711.60 5.80 2.84 8.60 -215.42

Local Positive

Day 1 2.23 1.28 1.50 1.74 42.50 2.26 1.31 1.73 42.20

Day 2 2.22 1.29 1.63 1.72 41.91 2.15 1.31 1.64 39.20

Day 3 2.07 1.25 1.52 1.66 39.75 2.05 1.31 1.57 36.19

mean 2.18 1.27 1.55 1.71 41.39 2.15 1.31 1.65 39.20

CV 4.08 1.75 4.52 2.44 3.50 4.86 0.10 4.94 7.66

WHO/BS/2014.2244

Laboratory 18


Screen

ratio

Confirm

ratio

Screen/

confirm

ratio

NR

%

correction

of ratio

Mix/

screen

ratio

Screen

ratio

Confirm

ratio NR

%

correction

of ratio

Mix/

screen

ratio

PNP

Day 1 0.92 1.04 1.09 0.96 -4.51

Day 2 0.97 1.07 1.02 1.05 4.48

Day 3 0.72 1.02 1.34 0.76 -31.63

mean 0.87 1.04 1.15 0.92 -10.55

CV 15.01 2.55 14.52 15.95 -178.16

Sample A

Day 1 0.96 0.92 0.96 1.05 4.31

Day 2 0.93 0.98 0.92 0.96 -4.69

Day 3 0.98 0.75 0.95 1.32 24.03

mean 0.96 0.88 0.94 1.11 7.88

CV 2.55 13.63 2.08 17.01 186.33

Sample B

Day 1 1.20 1.15 0.95 1.04 3.68 1.04 1.25 1.26 0.99 -0.66 1.08

Day 2 1.20 1.20 0.97 1.00 0.33 1.03 1.29 1.23 1.05 4.79 1.11

Day 3 1.25 0.87 1.03 1.43 30.13 1.04 1.27 1.17 1.09 8.03 1.06

mean 1.22 1.07 0.98 1.16 11.38 1.04 1.27 1.22 1.04 4.05 1.08

CV 2.18 16.56 4.13 20.53 143.48 0.37 1.56 3.78 4.53 108.34 2.19

Sample C

Day 1 1.64 1.26 1.20 1.31 23.49 1.15 1.71 1.37 1.25 20.04 1.20

Day 2 1.65 1.32 1.21 1.25 20.24 1.15 1.77 1.35 1.31 23.81 1.23

Day 3 1.67 0.99 1.22 1.69 40.92 1.16 1.71 1.33 1.29 22.24 1.18

mean 1.66 1.19 1.21 1.42 28.22 1.15 1.73 1.35 1.28 22.03 1.20

CV 1.01 14.66 0.73 16.90 39.42 0.51 1.98 1.61 2.42 8.59 2.14

Sample Z

Day 1 0.93 0.86 0.99 1.07 6.91 0.97 0.94 1.03 2.71

Day 2 0.93 0.92 0.98 1.01 1.16 1.00 0.94 1.06 5.59

Day 3 0.94 0.68 1.00 1.38 27.75 0.95 0.91 1.05 4.89

mean 0.93 0.82 0.99 1.16 11.94 0.97 0.93 1.05 4.40

CV 0.46 15.58 1.01 17.24 117.19 2.35 2.17 1.56 34.11

Local Negative

Day 1

Day 2

Day 3

mean

CV

Local Positive

Day 1 1.56 1.30 1.10 1.20 16.63 1.63 1.42 1.15 12.87

Day 2 1.61 1.36 1.15 1.19 15.96 1.19 1.73 1.39 1.25 19.73 1.28

Day 3 1.58 1.00 1.14 1.58 36.75 0.77 1.61 1.34 1.20 16.74 1.24

mean 1.59 1.22 1.13 1.32 23.11 0.98 1.66 1.38 1.20 16.45 1.26

CV 1.63 15.78 2.15 16.86 51.12 30.77 3.88 2.93 4.10 20.91 2.48

WHO/BS/2014.2244

Appendix 4: Collaborative study protocol

Collaborative Study on the proposed WHO 1st Reference Panel for Lupus Anticoagulant

(CS477)

Introduction

There is no single test used to diagnose patients with lupus anticoagulant (LA) and as such

diagnosis is usually based on the results of clotting tests such as dilute Russell’s Viper Venom

time (dRVTT) or sensitive Activated Partial Thromboplastin Time (APTT). Tests often

involve the mixing of patient plasma with normal plasma. The presence of LA leads to

prolongation of clotting times, which should be corrected in the presence of normal plasma.

However, full correction is not always observed and can be complicated by clotting factor

deficiencies or heparin treatment, so misdiagnosis can occur, especially in patients who are

weakly positive for LA. There is currently no standard available for the detection of lupus

anticoagulant and therefore the aim of this study is to assess whether a panel of lupus

anticoagulant reference materials are “fit for purpose” to increase the accuracy of diagnosis

and ensure the consistency of tests between laboratories.

Samples for Assay

There are 4 materials provided for assay, all are lyophilised plasma preparations containing

varying amounts of LA. They are labelled A, B, C and Z. Please also include your in-house

positive and negative controls in your assays. Fresh ampoules should be used on each day of

the study and samples should be tested in duplicate within each assay.

Storage and reconstitution of samples A, B, C and Z

Store all unopened ampoules at -20oC or below. Ampoules should be allowed to warm to

room temperature before reconstitution.

Directions for opening DIN ampoules

DIN ampoules have an ‘easy-open’ coloured stress point, where the narrow ampoule stem

joins the wider ampoule body. Tap the ampoule gently to collect the material at the bottom

(labelled) end. Ensure that the disposable ampoule safety breaker provided is pushed down

on the stem of the ampoule and against the shoulder of the ampoule body. Hold the body of

the ampoule in one hand and the disposable ampoule breaker covering the ampoule stem

between the thumb and first finger of the other hand. Apply a bending force to open the

ampoule at the coloured stress point, primarily using the hand holding the plastic collar.

Care should be taken to avoid cuts and projectile glass fragments that might enter the eyes, for

example, by the use of suitable gloves and an eye shield. Take care that no material is lost

from the ampoule and no glass falls into the ampoule. Within the ampoule is dry nitrogen gas

at slightly less than atmospheric pressure. A new disposable ampoule breaker is provided with

each DIN ampoule.

WHO/BS/2014.2244

Reconstitute the ampoule contents by adding 1 ml of distilled water. Allow the ampoule to

stand for 10 minutes at room temperature and aid reconstitution by gentle swirling. Transfer

contents to a plastic tube and store at 4oC prior to assaying. Testing should be completed

within 3 hours of reconstitution.

Assay Design

Please carry out your selected test(s) according to your normal laboratory protocol. Testing

should be carried out on three separate days, with a fresh ampoule(s) used each day. Testing

should be completed within 3 hours of reconstitution of the samples. Please vary the order of

the samples in each test by using a balanced order of testing, for example by following the

scheme below:

Position: 1 2 3 4 5 6 7 8 9 10 11 12

Day 1: Neg A B C Z Pos Pos Z C B A Neg

Day 2: A B C Z Pos Neg Neg Pos Z C B A

Day 3: B C Z Pos Neg A A Neg Pos Z C B

Neg – in-house negative control

Pos – in-house positive control

A – sample A

B – sample B

C – sample C

Z – sample Z

If you are carrying out several tests and the total volume required for all tests is more than 1

ml, you should have received more than one ampoule. If this is the case, please plan your

tests accordingly such that a test does not use material from two different ampoules of any

sample

e.g. dRVVT uses 600 µl and APTT uses 500 µl – please use the second ampoule for the APTT

rather than a combination of 400 µl from the first ampoule and the rest from the second

ampoule.

Please ensure that dRVVT screen and confirm are carried out on the same ampoule.

Results

Raw data (i.e. clotting times for each individual sample) should be recorded on the results

sheets provided. Please return your raw data and calculated ratios (if applicable) by 18th

January 2013 to:

[email protected]


WHO/BS/2014.2244

Appendix 5: Draft IFU

WHO/BS/2014.2244

WHO/BS/2014.2244 ENGLISH ONLY EXPERT COMMITTEE ON ...

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