1

Mahboubeh (Mandy) Rahmani, MD, FRCPC

Hematopathologist, QEII, Division of Hematopathology

Assistant Professor, Dalhousie Faculty of Medicine

mrahmani@dal.ca

Quality Assurance in Hematological Pathology

Jan 15th, 2021

Disclosures

•None

Acknowledgements

•Notes primarily shared by Dr. Ruth Padmore

2

Objectives

1. Review the Clinical and Laboratory Standards Institute (CLSI)

Quality System Essentials

• Principles of standard operating procedures and document control

• Document and material Retention times

• Recognize safety in the Laboratory

• Describe key features of assessment including internal quality control

and external quality control

2. List laboratory errors (pre analytic, analytic and post analytic) and

have an approach to incident management

3. List critical results –how are they handled

4. Describe test and instrument selection, validation and verification

Quality Management Hierarchy

• Laboratory quality is conformance to requirements, with the goal of

reporting results acceptable for patient care

• Reliable

• Accurate

• Timely

Management

• Management with executive responsibility

• Management representative

• Laboratory director

• Management review

• At least twice per year, many hold quarterly

• Key quality indicators will be reviewed

• Documented

CLSI Quality System Essentials

1. Documents and records

2. Organization

3. Personnel

4. Equipment

5. Purchasing and Inventory

6. Information management

7. Customer service

8. Facilities and safety

9. Process Control

10. Occurrence management

11. Assessment

12. Process improvement

1. Documents and Records

CLSI-quality system regulation for laboratory developed tests

Standard Operating Procedures Manuals (SOPs)

• Put together an SOP writing team:

• Team members: operations, training, quality

• Writing:

• Write for your audience, write content to fit the purpose

• Action items; put the verb first:

• Record the expiration date of the vial after opening

• Write the steps in the order they occur

• Modify the steps to prevent potential errors

• Use computers/automation where possible

• Design forms to capture results

• Approval:

• By lab section and lab director or designee

Record Management

• Collection, confidentiality, maintenance, access, and disposal of records

• Principles for document control include:

• Write and name the document

• Store the documents (written, electronic)

• Keep documents up to date

• Document any changes to the documents

• Use only current documents which have been approved

• All personnel should be knowledgeable re content

• Archive/destroy obsolete documents

• Records retention meets government, accreditation requirements

Medical Records Retention

• Physicians must ensure medical records are retained for a minimum

of the following time periods

• Adult patients: 10 years from the date of the last entry in the

record.

• Children: 10 years after the day on which the patient reached or

would have reached 18 years of age

College of Physicians and Surgeons of Ontario

https://www.cap-acp.org/guide_retention-human-biologic-material.php

Retention of Bone Marrow Specimens and Reports

• Bone marrow slides should be stored at least 20 years or

indefinitely, if possible

• Digital images and electronic reports may be stored indefinitely

• The duration of storage of bone marrow specimens and reports

should comply with (national) regulatory guidelines

ICSH guidelines for the standardization of bone marrow specimens and reports. Int J Lab Hematol 2008;30:349-365

Retention of Materials in the Hematology Laboratory

• Flow histograms including gating used for reporting: at least 2 years

• CBC tube: 48 hours

• Normal Peripheral blood slides: at least 7 days

• Abnormal Peripheral blood slides:

• In a hospital in Ontario: at least 10 years (or 10 years after 18thbirthday)

• In a community (commercial) lab: 1 years

Ontario Laboratory Accreditation (OLA), version 7.1, item VIII.4.2

Retention of Materials, Others

• Cytogenetic/molecular reports (neoplastic disorders): 10 years

• Cytogenetic/molecular reports (constitutional/inherited disorders):

20 years

• Test reports: 10 years

• Proficiency testing records: at least 2 years

• Electrophoresis gels and reports should be retained for at least 10

years (or for 10 years after the 18thbirthday, in the case of children)

Ontario Laboratory Accreditation (OLA), version 7.1, item VIII.4.2

Document Retention - Transfusion Medicine

2020 Canadian Standards Association

Examples of documents with 5 years retention time

Donor suitability assessment

Record of donation (i.e., all donation information other

than that specified above to support lookback/traceback)

Records of inspection of blood components before

release

Quality control testing of blood components, reagents,

equipment, and proficiency testing surveys

Product complaints

Quality assurance reports and records of audits

Temperatures of storage for blood components

Donor apheresis procedure records

Autologous donor collection record

Records of inspection of blood components before

release

Document Retention - Transfusion Medicine

2020 Canadian Standards Association

Examples of documents with 10 years retention time Examples of documents with 10 years retention time

Determination of temporary donor unsuitability (i.e.,

deferrals) Note: Indefinite deferrals are covered under Item A-7.

Documents generated during the traceback and

lookback processes

Note: Establishment policies could extend the retention

period for reasons outside the scope of this Standard,

(e.g., legal liability).

Post donation information that leads to product recall and/or donor

deferral

Record of transfusion or other final disposition

Blood component preparation Records of washing, pooling, or irradiating of blood

(transformation activities)

Master copies of superseded procedures and manuals (except for the

donor suitability procedures specified in Item A-5)

Record of final disposition of autologous blood

components, including identification of the recipient

Investigations and reports of the following donor and recipient events as

related to the safety of the product:

a) errors and accidents that could lead to serious adverse reactions; or

b) unexpected or serious adverse events, including adverse reactions

Individual personnel qualifications, training, and

Competency (10 years (after end of employment))

Document Retention - Transfusion Medicine

2020 Canadian Standards Association

Examples of documents with 50 years retention time

Date of donation Record of distribution, including exceptional distribution

and any recalls

Identifying information for the collected blood

components, including the identification of the collecting

facility and the numeric or alphanumeric identification of

the blood component

Record of final disposition of allogeneic blood

components, including identification of the recipient (for

transfused components)

The health care facility’s record of release for transfusion

of allogeneic components

The record of transfusion of allogeneic components

Documents describing the process and criteria for

assessing donor suitability and the dates that the process

and criteria were in effect

Record of release for transfusion, and record of

transfusion

for allogeneic components

Test results from the donor sample for transmissible

disease testing ABO, RhD, and clinically significant

antibody test results

Importation in urgent circumstances

Record of indefinitely deferred donors Record of distribution, including exceptional distribution

and any recalls

Document Retention - Transfusion Medicine

2020 Canadian Standards Association

Examples of documents with 1 year retention time Examples of documents with 3 years retention time

Date and time a recipient blood sample was drawn and

phlebotomist’s identification

Documentation of maintenance of critical equipment

Packing/shipment documents Documentation of validation of computer systems

Lot number of critical supplies for each process (transformation

activity) and the name of the manufacturer

Lot number of critical supplies for each donation and the name

of the manufacturer

Other Retention time

Documentation of calibration and validation of critical

equipment

Lifetime of the equipment

2. Organization

• Chart

• Reporting

• Responsibilities

3. Personnel

• Job qualifications

• Job descriptions

• Training

• Competency assessment

• E.g. direct observation of test performance and instrument

maintenance, recording and reporting results, PT/EQA and/or blind

sample testing, problem solving skills

• Ensure adequate staffing

• Professional development

4. Equipment

• Policies, process and procedures for operating equipment

• Records of Selection, Acquisition, Installation, Validation,

Calibration, Maintenance, Service and repair

5. Purchasing and Inventory

• Process, procedure and records of:

• Purchasing equipment, reagents, materials

• Inventory management

• Receipt, and storage of materials

• Listing of labs used, and record of results and samples sent, if using

reference laboratories

• Contracts, requirements, in case of the laboratory service to other

laboratories

Quality Management Workflow optimization:Lean and Sigma 6

• Lean 5-S: Sort, set in order, sweep, standardize, sustain

• Six Sigma: improve quality by decreasing variability

• Lean Six Sigma: combines Lean and Six Sigma to removed 8 kinds

of waste: time, inventory, motion, waiting, overproduction,

overprocessing, defects, skills

6. Information Management

• Process for receiving and handling patient information to be

• Secure and private

• Accessible

• Accurately transmitted to patient record containing proper info

• All processes must be validated

• In case of computer information system consider

• Storage and data back up

• Hardware/software system maintenance

• Interface and networks

7. Customer Service

• Provide accurate, timely, and reliable results

• TAT

• Customer surveys

• Critical results

Critical Results

• Life-threatening results needing immediate notification of the

patient’s health care provider

• Usually reported by telephone

• Read back of results

• Documentation of name of person receiving results

• Document that critical results have been communicated to the appropriate

care giver

Handling Critical Results

• Inform a hematopathologist of any unusual persistent serial critical values

• If unable to contact the appropriate person in a timely fashion to report the

critical value, document any difficulty

• Establish guidelines for patients with repeated critical results

• If the reported critical value remains critical, a repeat notification will not be

made

• If a patient returns after a period of 14 days and the parameter is critical, it will

be called

• INR & anti-Xa will be called each time the result is critical

• Establish what are these critical results for your laboratory, (related to

medical decision points)

Critical Results

References: (1) Hematology: McFarlane et al, Int J Lab Hematol 2015

(2) Coag: Pai M et al. Am J Clin Pathol 2011;136:836-841

8. Facilities and Safety

• Monitor, document, and control laboratory environmental conditions

that can influence quality of results:

• E.g. temperature, humidity, etc

• Safety of laboratory staff

• E.g. hazardous waste, personal protection equipment, etc

• WHMIS

• Workplace Hazardous Materials Information System

Safety in the Laboratory- WHMIS

• Three Key elements:

• Labels

• Supplier labels, workplace labels

• Safety data sheets

• Worker education

• training yearly

• Employers responsibilities: Label hazardous materials, provided SDS, train employees,

review training program annually

• Workers responsibilities: retrain each year, make sure hazardous materials are labelled,

follow safe procedures including wearing personal protective equipment (PPE), report

deficiencies to the supervisors

https://www.ccohs.ca/products/posters/pdfs/WHMIS_2015.pdf

Safety in the Laboratory

• Be aware of pertinent regulation and guidelines

• Identify and control hazards

• Have employee training in lab safety, ensuring knowledge how to use all

equipment and reagents safely

• Have up to date contact with occupational/employee health at your

workplace

• Have an emergency response plan and an accident investigation plan

• Evaluate lab safety program at regular intervals: good record keeping of

training/incidents, written safety policies, feedback from employees,

benchmark (what are your colleagues doing)

• Use risk management tools to improve safety (e.g. FMEA)

Safety in the Laboratory- Risk Management Tools

• Failure Mode and Effects Analysis (FMEA):

• Prospective analysis of potential safety failures

• Each step in a process evaluated for potential to fail and cause harm.

Safety Representative Responsibilities

• Provides safety expertise, advice, guidance

• Ensures safety orientation and training of employees is conducted

• Assists with risk management strategies (e.g. FMEA)

• Surveys work sites for safety deficiencies and to recommends

solutions/safety programs

• Posts minutes of safety committee meetings

Vanderbilt Model to Address Unprofessional Behavior

9. Process Control

• Verification and documentation of in laboratory, new or changed

processes and procedures

• Standard operating procedures (SOP)

• Validation

• Quality control (schedules, etc)

10. Occurrence Management

• Processes and procedures for detection, documentation and

investigation of unexpected occurrences

• Lab Errors

11. Assessment

• To determine if regulations, standards and requirements are being

met

• Accreditation

• Internal assessment (e.g. audits, quality indicators)

• External quality assessment (EQA, proficiency testing)

• where no EQA exists:

• Split samples with other laboratories

• Peer group assessment

• Compare QC results to other labs using that vendor’s device or reagent

Audits

• Systematic review using explicit criteria

• Compliance audit: determines conformance to a set of rules

• Management audit: determines conformance to a set of rules and

determines the effectiveness of rules in achieving an

organization's goals

Audits

• Items to include on a audit report form

• Purpose of audit

• Scope of audit

• Standards and reference documents

• Overall summary

• Summary of positive practices

• Summary of nonconformances

• Objective evidence (observations, facts)

Quality Indicators

• Use quality indicators to monitor and evaluate the laboratory's

standards of performance, contribution to patient care, and quality

improvement of lab services

• QI must have: objectives, methodology, interpretation, limits, action

plans and duration of measurement, documentation

Quality Indicators: Examples

• Analytic: QC and EQA performance

• Pre-analytic processes (specimen transport time and conditions,

specimen acceptability rates, wrist band identification checks)

• Post-analytic processes (reflexive testing, turn around times [TAT])

• Customer satisfaction (surveys), patient wait times in collection

areas

• Specimen rejection rates, specimen labelling errors

• Monitoring of privacy/confidentiality

• Work related injury monitoring, safety

• Wastage rates (reagents, blood products)

External quality assessment (EQA)

• EQA samples are to be handled the same way as patient samples

• Results comparison

12. Process Improvement

• Quality Assurance (QA)

• A system for continuous review and planned systematic actions to ensure the

defined quality objectives were met

• Quality Control (QC)

• Known analytes used to measure, evaluate and monitor errors in patient

samples

• Quality Improvement (QI)

• Understanding of what the problems are and investigation to improve

process/outcome

• Ongoing education and competency following error management

Quality Improvement (QI)

• PDSA Cycles (Plan-Do-Study/Check-Act)

http://www.hqontario.ca/

Change Management

• Kotter’s 8-Step Process for Leading Change

• Create a sense of urgency

• Build a guiding coalition

• Form a strategic vision and initiatives

• Enlist a volunteer army

• Enable action by removing barriers

• Generate short term wins

• Sustain acceleration

• Institute/anchor change

Lab Errors

• An adverse medical event is an injury related to the patient’s

medical care and not due to their medical condition

• The just culture:

• Most errors are honest human errors, which require system fixes

• Focusing on system fixes avoids “name, shame and blame”

culture

• Accountability

• Confront situations where employees are misfit to their job

duties

Types of Errors

1. Unintended human errors

Cognitive errors = mistakes, errors involving thought or judgment,

may be due to lack of knowledge (remedy: more

training/supervision

Non-cognitive errors = slips: lapses in concentration while

performing repetitive tasks (remedy: process improvement:

checklists, automation, removal of distractions)

2. At-risk behaviors (remedy: better adherence to existing plans)

3. Reckless behaviors: (remedy: better adherence to existing plans)

QUALITY ASSURANCE

POST-ANALYTICALANALYTICALPRE-ANALYTICAL

• Record keeping

• Reporting Accurate

results

• TAT

• Validation

• Day controls/QC material

• Proficiency testing

• Direct observation reviews

• Patient identification

• Sample collection

• Test ordering

• Personnel competency test

• Evaluation

• Sample transport

• Sample receipt/accessioning

Reporting results

acceptable for patient care

Lab Errors

• Most lab errors occur at the pre-analytical phase

• Specimen collection

• Ordering the wrong lab test

• Errors on requisition, unlabeled specimen

• Mislabeled specimen (wrong blood in tube –WBIT)

• Incorrect tube

• Incorrect order of draw (1 blood culture, 2 citrate (3.2% Na

citrate for INR), 3 serum, 4 heparin, 5 EDTA, 6 fluoride/glucose)

• NSQ: underfilled Na citrate or high Hct: prolonged PTT, INR

Lab Errors - Pre-analytical

• Specimen Transport:

• Delayed transport

• Specimen lost

• Temperature too high: degradation of Factors V and VIII.

• Temperature too cold: loss of Factor VIII and vWF

• Pneumatic tube transport (validate pneumatic tube system)

• Specimen Processing

Lab Errors - Pre-analytical Examples

• Patient is on DOAC but this is not documented: e.g. factitiously

overestimate Protein C and Protein S using clot based assays

• Reference lab: aliquot received for Factor V testing (not in original

tube), but sample was collected in EDTA not citrate (coag samples

collected in EDTA show increased INR, increased PTT, low factor V

and VIII levels with non-parallelism, high K+ and absent Ca2+)

• Measurement of unfractionated heparin using PTT: centrifuge within

1 hour and test plasma within 4 hours because of potential for

heparin neutralization by platelet factor 4

Lab Errors - Pre-analytical - WBIT and Delta Checks

• Delta check to identify WBIT errors

• Compares the present value with the previously reported value

• Delta check failure:

• The difference between the current value and the previous value

exceeds the threshold set by the lab

• E.g. 30% Hgb, 7% MCV, 50% platelets

• Lab result either not reported, or reported with a flag

• To improve PPV of delta checks:

• Velocity of change, relative change, maximum look-back time, multi-

analyte delta check (machine based learning)

Rosenbaum et al. Am J Clin Pathol 2018;150:555-566

Lab Errors – Analytical and Post-analytical

• Analytical errors

• Safe guards include IQC, EQA, specimen tracking, automation

• Post-analytical errors:

• Results delayed

• Results not reported

• Results reported to wrong provider

• Incorrect post-analytical data entry error

• Incorrect test results interpretation/Results not understood by

clinicians (brain to brain)

Quality Control (QC)

• Internal assessment of analytical quality

• Used to increase the probability that each result reported by the lab is

valid

• Monitors precision and accuracy of analytical method on a daily

basis

• Accuracy: Degree of closeness of determined value to the true value

• Precision/ imprecision: dispersion of repeated measurements about the

mean

Quality Control

• Selection of control material:

• 3 levels, low, normal, high, clinically relevant levels/medical decision points

• Commercial QC from same manufacturer as instrument

• Patient control

• Frequency of running QC

• At least once a day, after calibration

• Patient controls: after reagent changes, following lot changes, maintenance,

throughout analytical run

• Interinstrument quality control comparison

• Patients samples

• At least weekly

Reference: Johnston A et al. Guidance for quality control practices and precision goals for CBCs based on IQMH

patterns-of-practice survey. Int J Lab Hematol 2019;41:15-22

Monitoring QC

• Use QC rules which detect clinically important errors while

minimizing false rejections

• Have at least one rule for random error and one rule for systematic

error

• Track QC with standardized control chart (Levey-Jennings chart,

radar plot), QC software: readily available for review by all staff

Reference: Johnston A et al. Guidance for quality control practices and precision goals for CBCs based on IQMH

patterns-of-practice survey. Int J Lab Hematol 2019;41:15-22

QC Target Limits

• Establish target mean and SD for each separate instrument, using

20 QC points over 10 runs

• Run current lot number concurrent with old lot number

• Use patient sample to rule out matrix effect (use normal and

abnormal patient)

Reference: Johnston A et al. Guidance for quality control practices and precision goals for CBCs based on IQMH

patterns-of-practice survey. Int J Lab Hematol 2019;41:15-22

QC with patient samples: Xb

• Bull’s moving average, X-bar-B

• Consecutive patient results compared with the running mean

• Only results within the normal range are averaged

• Indices tracked: MCV = Hct/RBC, MCH = Hgb/RBC, MCHC = Hgb/Hct

• When to investigate:

• Bull's mean of one batch is outside 3% OR

• Average of three consecutive Bull's means is outside 2% limits

• Advantages: savings on QC reagent costs, detects in-run analytical

error, helps troubleshoot cause of errors

-

Monitoring Quality Control

Wikipedia.org

Lab Errors

• Random errors:

• Affect precision

• Do not affect entire batch

• Systematic errors (bias):

• Affect accuracy

• Affects all samples in batch equally

• Detected by testing controls

Westgard Rules

• 10x 10 # of points falling on same side of mean

• Used to detect very small systematic changes

• R4s Shift in consecutive data >4SD

• Used to detect random error

• 13s 1 point falling outside 3 of SD

• Cannot differentiate between random and systematic error

• 22s and 41s Multiple consecutive points falling outside # of SD

• Used to detect systematic error

Management of QC Out of Control

• Discontinue testing

• Notify clinicians of any erroneous results released

• Determine root cause

• Implement corrective action

• Document all actions

• Repeat test patient samples from last acceptable quality control

• Follow-up with risk management: review QC failures and their

causes and look for solutions

Investigation of Lab Errors: Root Cause Analysis Example

• The freezer alarm sounds (the problem)

• Why?-The freezer temperature is too warm (first why)

• Why?-The freezer is not functioning properly (second why)

• Why?–There has been dust/dirt build-up on the back of the freezer.

(third why)

• Why?–Facilities maintenance has not vacuumed/cleaned the back of the

freezer according to policy (fourth why)

• Why?-Facilities maintenance did not think that vacuuming the back of

the freezer was needed/important (fifth why, a root cause)

• Why? –No communication from lab staff that this was important and no

form/record to document when task was completed

Investigation of Lab Errors - Root Cause AnalysisFishbone Ishikawa diagram

Instrument Selection

• Gather information about the methods in question

• From vendor

• From literature

• From other laboratories that run the method

• Conditions to be considered:

• Dimensions of the device and space in the lab

• System characteristics:

• Throughput of the instrument, sample/h, peds, ease of use

• Technical skill required

• Maintenance/ calibration frequency

• Reagent required/preparation, QC material

• Financial considerations: cost of device, cost per test, etc

• Level of dependability (manual intervention)

• Safety (biohazards)

Principles for Test Set Up

• Define appropriate specimens, collection methods, transport and storage

conditions

• Write QC, calibration and new lot number verification procedures

• Set up validation rules

• Check interphases with lab information systems

• Write test procedure, write procedure for LIS down time

• Obtain lab license for the test

• Enroll in proficiency testing program for the new test

• Train staff and assess staff for competency

• Establish critical values

• Establish interpretative comments

• Define clinical indications for test and educate caregivers re indications and

interpretation

• Specify suppliers and ordering procedures

• Define instrument maintenance

Validation

• Confirmation, through the provision of objective evidence, that the

requirements for a specific intended use or application have been

fulfilled• According to CLSI guidelines:

• Validation should in principle be performed by the manufacturer for

the intended scope

• Verification by the clinical laboratory of the manufacturers claim is

sufficient

Method Validation

• Precision (reproducibility)

• Accuracy (method comparison)

• Analytical sensitivity (limit of detection)

• Analytical specificity (including interfering substances)

• Analyte stability

• Patient correlation studies

• Linearity

• Carryover

• Analytical measuring range, reportable range

• Reference intervals, normal range

Inclusion and Exclusion Criteria

Example: automated hematology analyzers

• Inclusion criteria

• EDTA specimens collected in the tubes normally used by the site

• K2EDTA preferred if options available

• Test samples within 8 hours of phlebotomy

• To minimize aging effects on CBC mneasurands

• Exclusion criteria

• Visibly hemolyzed specimens

• Visibly clotted specimens

• Insufficient blood collected

• >8h old

• Unless an aging study is part of the experiment

• Analyte stability

Precision (Reproducibility)

• Within Run Precision:

• Assay each level of control material 20 times in a single batch

• Between Run Precision:

• Assay each level of control once per day for 10-20 days

• Calculate the mean, standard deviation, coefficient of variation for

each control material

• Compare with manufacturer’s published performance specification

Accuracy (Method Comparison)

• Analyze samples (e.g. 100 samples for PLT concentration, or 400-

cell WBC differential)

• Samples on both new and old/reference methods (run within 2 hours

of each other)

• r value of 1 is perfect! (aim for r2 >0.95)

Vis JY, Huisman A. Verification and quality control of routine hematology analyzers. International journal of laboratory hematology.

2016 May;38:100-9.

Interfering Substances

• Analyte Specificity

• Ability to unequivocally assess the analyte in a standard specimen in

the presence of other components (interferences)

• Should be recognized and procedures for dealing with them

required; examples:

• Icteric/Lipid plasma – saline replacement procedure

• Cryoglobulins/Cold agglutinins – warm sample

Detection of Interferences

Interference (examples) Measurands Potentially Affected

Leukocytosis Hb, Plt, RBC, MCV

RBC rouleaux or agglutinates RBC, MCV

Plt aggregates Plt, WBC, differential

RBC microcytosis Plt

Lysis-resistant RBC (Hb-S, Hb-C) Hb, WBC, differential, NRBC

Microclots MCV, Plt, MPV

Thrombocytosis, macrothrombocytes EBC, RBC, Hb, Plt, MPV

Lipemia, chylomicronemia Hb, WBC, differential, Plt, eosinophils

Parasites (e.g. malaria, filaria) Eosinophils, monocytes

Hyperbilirubinemia Hb

CLSI H26-A2: 2010 Validation, Verification, and Quality Assurance of Automated Hematology Analyzers, 2nd edition

Specifications Overview

For hematology:

• Limit of blank

• Background noise

• Lower limit of detection (LLoD)

• Average of the background results plus a constant multiplied by the SD of the

background results

• Lower Limit of quantification (LLoQ)

• The lowest WBC and Plt concentrations used, %CV measured to identify which

concentration

https://validationmanager.com/

Carry Over

• Expressed as a percent effect of one sample on the

succeeding sample

• “High target value” (HTV) concentrations are

processed in triplicate, followed by three “low target

value” (LTV) specimens (e.g. WBC, RBC, Hb, and Plt)

• Calculation:

• %Carryover=(𝑳𝑻𝑽𝟏−𝑳𝑻𝑽𝟑)

(𝑯𝑻𝑽𝟑−𝑳𝑻𝑽𝟑)x 100

Linearity (Analytical Measuring Interval)

• To provide results proportional to the concentration of the analyte

within a given range

• Duplicate dilution series

• Plot average values against % dilution; Line of best fit

• Acceptance criteria based on the statistical correlation coefficient of

linear regression

Analytical Reportable Range

• Analytical measurement range (AMR)

• The interval between the upper and lower analyte concentrations for which the

analytical method has demonstrated a suitable level of precision, accuracy, and

linearity without pretreatment (dilutions)

• Reportable range (RR)

• Range of analyte concentrations in which the analytical method demonstrates

suitable level of precision, accuracy, and linearity with pretreatment (dilutions

or concentrations)

Reference Range

• Collect samples from a healthy population

• Should not be hospitalized or clinic patients unless necessary (pediatric,

geriatric)

• Questionnaire can be used for exclusion criteria

• Written consent form required

• 120 (ICSH recommendations) for each age/gender reference interval run over

10 –20 day

• Reference range is mean +/- 2SD, if results follow gaussian distribution

• Should be verified when established; e.g.

• 20 for each age/gender reference interval run over 3 –4 days

• ≤10% outside range of 95% confidence interval acceptable

Calibration

• Adjusting the analyzer using a traceable calibrator

• Set-point

• For automated hematology analyzers, whole blood cross-reference

check is performed

• Calibrator characteristics

• Assigned values

• Stability

• Labeling

Constant and Proportional Bias

• Difference between the test results and the true value

• zero bias calibration factor = 1.00

Calibration Verification (Verification of Set-Point)

• Recommended after changes of reagent lots, major maintenance,

significant change in QC data, or when recommended by the

manufacture

• Materials for calibration may include, but are not limited to

• Calibrators used to calibrate the analytical measurement system

• Materials provided by the vendor for this purpose

• Previously tested unaltered patient specimens that are still “fresh”

• Primary or secondary standards or reference materials with matrix

characteristics and target values appropriate for the method

Statistics

• Mean Average value of a group of test results

• SD = 𝑿−𝒎𝒆𝒂𝒏𝟐

𝒏−𝟏

• Coefficient of Variation (%CV): 𝑺𝑫

𝒎𝒆𝒂𝒏x100

• Expressed as a percentage

• Sensitivity 𝑨 (𝑻𝑷)

𝑨 𝑻𝑷 +𝑪(𝑭𝑵)

• Specificity 𝑫 (𝑻𝑵)

𝑩 𝑭𝑷 +𝑫(𝑻𝑵)

• Positive predictive value 𝑨 (𝑻𝑷)

𝑨 (𝑻𝑷)+𝑩(𝑭𝑷)

• Negative predictive value 𝑫 (𝑻𝑵)

𝑪 𝑭𝑵 +𝑫(𝑻𝑵)

Positive Negative Total

Positive A B A+B

Negative C D C+D

Total A+C B+D

Reference method

New

meth

od

ROC Curves

Point of Care Test Set Up

• Which instrument to choose, who will pay for it, verify billing

• What test(s) will be performed, what is the specimen type

• Where will testing be performed by who (qualifications of the

personnel)

• Set up IT connectivity, set up QC and PT/EQA including review of

these results

• Appoint a POC coordinator: oversees training and competency

assessment, writing SOP, etc.

Point of Care Device (POCD)

Bland-Altman Plot Linear regression

Louw S, Mayne AL, Wan YO, Mayne E. Validation of the Mission Point-of-care device for haemoglobin measurement. International

Journal of Laboratory Hematology. 2020 Oct 3.

Useful Websites

• Lab Management: TM committee:

http://transfusionontario.org/en/documents/?cat=transfusion

• CMA code of Ethics and Professionalism, updated 2018 link:

• https://www.cma.ca/cma-code-ethics-and-professionalism

• www.WHMIS.org

• www.Westgard.com

• www.islh.org education –webinars: Hematology Test Validation. Dr.

Kandice Marchant

References

• CLSI-quality system regulation for laboratory developed tests

• Johnston A, Bourner G, Martin T, McFarlane A, Good D, Padmore R, Raby A, Aslan B. Guidance for quality control

practices and precision goals for CBCs based on IQMH patterns-of-practice survey. International journal of laboratory

hematology. 2018 Aug 23;41(1):15-22.

• Rosenbaum MW, Baron JM. Using machine learning-based multianalyte delta checks to detect wrong blood in tube

errors. American Journal of Clinical Pathology. 2018 Oct 24;150(6):555-66.

• Louw S, Mayne AL, Wan YO, Mayne E. Validation of the Mission Point-of-care device for haemoglobin measurement.

International Journal of Laboratory Hematology. 2020 Oct 3.

• Hickson GB, Pichert JW, Webb LE, Gabbe SG. A complementary approach to promoting professionalism: identifying,

measuring, and addressing unprofessional behaviors. Academic Medicine. 2007 Nov 1;82(11):1040-8.

• Vis JY, Huisman A. Verification and quality control of routine hematology analyzers. International journal of laboratory

hematology. 2016 May;38:100-9.

• Hoo ZH, Candlish J, Teare D. What is an ROC curve?.

• CLSI H26-A2:2010 Validation, Verification, and Quality Assurance of Automated Hematology Analyzers, 2nd Edition

• 2020 Canadian Standards Association

• Hematology: McFarlane et al, Int J Lab Hematol 2015

• Pai M et al. Am J Clin Pathol 2011;136:836-841

Any Question?

mrahmani@dal.ca