Quality Assurance & Quality Control in Clinical Laboratory...
Transcript of Quality Assurance & Quality Control in Clinical Laboratory...
Quality Assurance & Quality Control
in Clinical Laboratory
(Specific criteria-112)
Dr. Gajendra GuptaHead of Department
Dept. of Pathology and Transfusion MedicineSantokba Durlabhji Memorial Hospital,
Cum Medical Research Institute,
Bhawani Singh Marg, Jaipur
Quality is not easy to define:
Donabidian (1990) defined quality in health
care by using following attributes
• Efficacy and effectiveness
• Efficiency & optimality
• Acceptability & legitimacy
• Equity
• Efficacy and Effectiveness describes the best
possible care & outcome under optimum
condition
• Efficiency and optimality related to absolute
and relative cost of improving or
maintaining health
• Acceptability and legitimacy are concerned with
the wishes, acceptation and value of the patient
& community
• Equity looks after social needs and distribution
of health care.
Quality Assurance can be seen as tripod
Quality Assurance
Assessment &
Monitoring
Program Development Quality
improvement
When this philosophy is applied to laboratory it
is seen as
• Clinician must order investigation that are effective for
diagnosis or monitoring the condition of patient
• The overall cost of labs investigation must be less
than expected benefits.
• The laboratory measurement must be acceptable to
the patient ,clinician and community.
• The laboratory measurement and examination should
be available to all who need them at cost acceptable
to society.
Component of Quality Assurance program
Identification of Relevant Quality Goal
Sufficient resources to meet them
Plans & Procedures for assessing & monitoring quality
Procedures to respond to inadequate quality &
improving quality
Plan for reviewing the effectiveness of Quality
Assurance program & modifying it when necessary
Management requirement
Two requirement
Technical requirement
International Standards
ISO 15189 specific for Clinical Laboratory
• Specific criteria for accreditation of
medical laboratories (NABL-112)
Scope for which accreditation is
applicable.
• Clinical Biochemistry
• Clinical Pathology
• Hematology & Immunohematology
• Microbiology and serology
• Histopathology
• Cytopathology
• Genetics
• Nuclear Medicine (in-vitro test only)
Type of laboratory
• Small Laboratory-up to 100 patient/day
• Medium Laboratory-101-400 patient/day
• Large Laboratory->400 patient/day
Personnel
• Authorized signatures shall demonstrate
knowledge and competence in the concerned
specialty
• Qualifications and disciplines for being
authorized signatures are specified.
Sl. No. Qualifications Disciplines for being authorized signatory
A M.D. (Pathology) Histopathology, Cytopathology, Clinical Pathology, Haematology,
Clinical Biochemistry, Nuclear Medicine (in-vitro tests), routine
Microbiology and Serology, Genetics, Flow Cytometry and
Molecular Biology
B M.D. (Microbiology) Microbiology and Serology, Flow Cytometry, Molecular Biology,
Clinical Pathology, routine Haematology and routine
Biochemistry
C Ph.D. (Microbiology) with
M.Sc. (Medical
Microbiology)
Microbiology and Serology, Clinical Pathology, Flow Cytometry,
Molecular Biology
D M.D. (Biochemistry) Clinical Biochemistry, Clinical Pathology, Nuclear Medicine (in-
vitro tests), Flow Cytometry, Molecular Biology, Routine
Haematology, Routine Microbiology and Serology
E Ph.D. (Biochemistry) with
M.Sc. (Biochemistry)
Clinical Biochemistry, Clinical Pathology, Nuclear Medicine (in-
vitro tests), Flow Cytometry, Molecular Biology
Sl.
No.Qualifications Disciplines for being authorized signatory
F M.S. (Anatomy)/ Ph.D.
with M.Sc. (Human
Anatomy)/ Ph.D.
(Genetics)/ Ph.D.
(Applied Biology)
Genetics
G Medical Degree with
specialized (post
graduate) qualification
in nuclear medicine
such as Diploma in
Radiation Medicine
(DRM), M.D./ Ph.D./
M.Sc. in Nuclear
Medicine
Nuclear Medicine. It is necessary that the person
concerned holds a certificate from BARC on the use of
radioisotopes and RIA, this is the mandatory
requirement of AERB
H M. D. in Lab Medicine Clinical Pathology, Haematology, Clinical Biochemistry,
Nuclear Medicine (in-vitro tests), routine Microbiology
and Serology
I DCP with 7 years
experience
Histopathology, Cytopathology, Clinical Pathology, Haematology,
Clinical Biochemistry, Nuclear Medicine (in-vitro tests), routine
Microbiology and Serology
J MBBS with three years
experience in medical
laboratory
Routine Clinical Biochemistry, routine Haematology, routine
Microbiology and Serology, and Clinical Pathology.
K M.Sc. in Medical
Biochemistry with 5 years
experience or M.Sc. in
Biochemistry with 7 years
experience in Medical
laboratory
Clinical Biochemistry, Clinical Pathology, routine Haematology,
routine Microbiology and Serology.
L M.Sc. in Medical Microbiology with
5 years experience or M.Sc. in
Microbiology with 7 years
experience in Medical laboratory
Microbiology and Serology, Clinical Pathology, routine Clinical Biochemistry,
routine Haematology.
Sl. No. Qualifications Disciplines for being authorized signatory
• DNB is equivalent to MD/MS.
• NABL may relax qualification in those exceptionalcases where persons have demonstrated compliance andestablished their credentials
• At time of emergency DMLT with 1 year experience orM.Sc. MLT may provisionally authorize the reportwhich must be checked and countersigned byauthorized signatories afterwards
• Graduate in Medical Laboratory Technology
• Diploma in Medical Laboratory Technology with the course of at least two
years duration
• Diploma/ certificate in Medical Laboratory Technology with the course of at
least one year duration and two years of experience in a medical laboratory.
• Graduate in Science with one year experience in a medical laboratory.
• Diploma in medical radiation and radioisotope technology (DMRIT)
• Cytotechnologist – ‘a, b, c and d’ with additional certification in
cytotechnology by the Indian Academy of Cytology for screening of
exfoliative cytology.
• A laboratory may employ up to 25 % of the staff with science in matriculation
having at least 10 years experience in a medical laboratory
Qualification Norms for Technical Staff
Training of Staff
• The laboratory shall have a system of
imparting necessary training to technical staff
of various levels
• These shall be a system where technical
person receives adequate training in the
operation of new analytical equipment.
• Staff making impression and opinions shall
regularly update their knowledge
• Patient reception
• Sample collection
• Workbench
• Equipment
• Storage of volatile and inflammable reagents
• Radioisotope related work as per the regulatory agency
(AERB) requirement
• Washing
• Isolation for biohazardous materials
Accommodation and Environmental
Condition
Cont..
Accommodation and Environmental
Condition
• Adequate lightning , power plug and uninterruptedpower supply
• The lab shall have procedures in place to ensure theintegrity of refrigerated/frozen sample/ reagents etc,in the event of electric failure .
• Sample collection room with separate room for
cytology procedures shall be present.• Effective separation of lab to avoid cross
contamination shall be present.
Laboratory Equipment
• All the consumables shall be stored properly and
used within their expiry dates
• The label should bear contents quality ,
concentration, date received / prepared , date of
opening, storage requirements and expiry dates
wherever applicable.
• All consumables shall be procured from standardreputed sources.
• Each lot shall be checked for performance againstearlier tested in use reagent lot or its suitablereference materials before being placed in service.
• Automated analyzer such as cell counters clinicalbiochemistry auto analyzer, automatedcoagulometer , elisa reader etc. shall be calibratedat least once a year
• The equipment shall be calibrated from NPL, orNABL accredited calibration laboratory
What is Calibration ?
Calibration is comparing of measurement device
against to a standard of known and greater accuracy
to detect and correct any variation from required
performance specifications of measurement device.
A standard in a measurement is considered the
reference which is maintained by the National and
International body.
Why measurement must be traceable?
• Traceable measurements ensure the uniformity of
manufactured products and
• Remark in the development of technology
• To support equity in trade as well as compliance to
regulatory law and standard
• Assure the users with of the confidence and
accuracy of the process
• Validate the whole process
In-house Calibration
• pH meter
• Specrophotometer and colorimeter
• Chromatograph
• Electrophoresis
• Microscopes
• Temperature-controlled equipment
• Pipettes
Calibration Internal Depends Upon
• Ruggedness of Equipment
• Frequency of Use
• Life of Equipment
• Quality and periodicity of maintenance
Minimum Period of Calibration
Item Maximum period
between successive
calibration & checks
Procedure and comments
Autoclaves One year *Check on effectiveness of sterilization
with each cycle
Balances and scales One year Balances with in-built calibration check
facility must also have six monthly checks
Electronic balances with more than one
range must have six monthly checks carried
out on all ranges
Checks include repeatability checks and
one-point check using a known mass close
to balance capacity
Biological safety
cabinet
One year *Colony count at least once in a week
Centrifuge Every six months (where
operating speed is
specified)
Tachometer (mechanical stroboscope or
light cell type) calibration of the timing
device and, where appropriate, the
temperature measurement device will be
required. In addition, performance testing
is recommended for specific applications.
Manometers:
Reference Working
Five years
One year
Check Fluid every three years
Check against reference
Masses One year ASTM E617
Piston-operated
volumetric apparatus
pipettes and
dispensers
Initial and every six
months
AS 4163
For gravimetric checks, volume delivery
and weighing under specified conditions
must be repeated at least ten times. For
adjustable devices check volume delivered
at several settings. Delivery of volumes
less than 100 microlitre may be verified by
spectrometry using a dye solution.
Item Maximum period
between successive
calibration & checks
Procedure and comments
Diluters Six months *Check volume delivered at settings in use.
Check sample and diluent volumes or
dilution ratio and total volume
Thermometers
Working
(Liquid in glass,
resistance, electronic)
One year Check against a calibrated reference
* Initial check at sufficient points to cover
the expected working range followed by six
monthly checks at ice-point within the
working range
Errors can occur at three level
• Pre-analytical phase
- Clinician may order the wrong assay
- Patient may not undergo proper preparation.
- Specimen collection may not be proper
- Transportation can hamper result if not proper
- Sample handling and storage
• Analytical phase
- Assessment of results in this phase is done by
- Accuracy
- Precision
• Post Analytical phase
- Less and few quality problem
- Report generation time
- Delivery of report
- Interpretation of result
Pre Examination Procedure
• Proper documented primary sample collection
manual should be present.
• The laboratory shall not accept sample with
labile /unstable analyte collected from other
sources.
• Space for clinical data shall be present in
request form and shall be duly filled.
• Procedure for acceptance/rejection criteria for
primary sample should be documented
• Specimen for culture must be processed
immediately.
• Consent form and pre testing counseling where
required shall be taken.
Examined specimen shall be kept for re-
examination and/or additional test in
• Clinical Biochemistry-3 days
• CBC & reticulocyte –6-8 hrs.
• Hb electrophoresis-1 weak
• Bone marrow slide-5 yrs
• Microbiology-24 hrs
• Serology/Immunology-3 days
• Clinical Path-24 hours
• Specimen of Histopathology-15 days
• Slides/Block-5 yrs
Examination Procedures
• The examination procedures used in lab shall be
from accepted test books, Journals or international
accepted methods.
• If lab develops its own method then it shall be
thoroughly validated.
Validation of Test Method
What is Validation ?
• The concept originated in analytical
chemistry to verify that a method provided an
accurate and representative value for the sample
employed under the conditions used.
• Now same can be applied to system validation also
Method Validation – What is it ?
VALIDATION = ERROR ASSESSMENT
Estimation of how much error might be
present in a test result produced by a
method in our laboratory.
Method Validation- Why is it
necessary to validate a new method
Method performance is affected by many factors:
– Changes in manufacturing from the production
of prototypes to final field instruments
– Effect of shipment and storage
– Local climate conditions in your lab e.g. temp,humidity
– Quality of water
– Stability of electrical power
– Skills of the operators.
Type of Test
Simple Tests -Need not validate
Unmodified Tests - Validation is required
Modified Tests - External validation is required
Method Validation
Validation = estimating error
Essential components of MV:
1) Estimating imprecision (random error)
2) Estimating inaccuracy (systematic error)
3) Verifying reportable range (linearity)
4) Verifying reference intervals (normal reference range)–
SOP’s
• All the process/procedure and methods followed in
laboratory shall be documented and followed
Microbiology
• All CLSI recommendations need to be followed
• Antibiotics shall be as hospital antibiotic policy.
• HIV testing needs to follow NACO guidelines.
Histo-pathology
• Grossing shall be done by competent perform
• Frequency of changes of chemicals needed to to
defined
• Proceeding for frozen section shall be laid down
• Turn around time not exceed 30 minutes
• Every samples have specified duration in which test
should be performed
• CBC-within 8 hrs
• Coagulation studies-4 hrs
• ESR-6 hrs
• Reticulocyte count-24 hrs
Haematology
Assuring quality of examination
procedure
• There has to be documented and established
procedure for monitoring and evaluating analysis of
testing processes.
• Certified control materials should be continuously
used in all sections wherever possible. The number
of controls can vary according to the number of test
done.
• The daily QC values shall be documented on Levy
Jennings curve or CUSUM chart and CV % from
monthly QC data shall be calculated.
Mean 1 SD 2 SD 3 SD
SD is a measures of dispersion of the value and is calculated
as
(X-X)2
SD = -------------
(n-1)
For practical convenience SD is converted to
the coefficient of variation (CV)
SD
CV=-------- x 100
x (Conc. of analyte)
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o 5 10 15 20
+2 SD
-2 SD
Time (Days)
Rules to follow for accepting/rejecting
QC control values
When one level QC material is used
• Any reading outside 3 SD (13S)
• Two consecutive values are outside 2 SD on same
side but within 3 SD (22S)
• Ten consecutive values are above or below mean but
within 2 SD (10X)
When 2 level QC Material are used
• Any QC value is outside 3 SD (13S)
• Both QC value are outside 2 SD on the same side but within 3SD (23S)
• Difference between both QC values is >4 SD (R4S)
• Ten consecutive values of same level are on one side of mean(10X)
• Five consecutive values of one level and five consecutivevalue of other level QC are on same side of mean but within 2SD(10X)
Flow chart should be made to
manage “Out of control situation”
• Search for recent events that could have caused changes
• Examine environmental condition
• Follow manufactures troubleshooting guide
• Refer to manufacturer of equipment, reagents or QC/Calibrator vendor.
• In the situation where more than one type of
equipment are used to do same test they shall also give
comparable result
• For small labs where stable haematology controls are
not available duplicate test on patient sample can be
done with calculation of SD of difference between the
result on 10 duplicate samples and determination of 2
SD limits.
• Subsequent duplicate values should be within these
defined limits.
• Microbiology lab shall practice quality control of various
procedures for bacteria identification.
• Control strains of known susceptibility should be used
along with the tests sample while performing
susceptibility QC.
• Stains for Acid Fast Bacilli should be checked with
known positive and negative control organism.
Histopathology
• When repeat specimen from same patient is received
all previous slides must be reviewed and reflected in
the final report
• Frozen section results must be compared with the
final assessment and both result must be reflected in
the final report
Uncertainty of measurement
• Where relevant and possible uncertainty component shall be worked out
• Sources that contribute to uncertainly way include
• sampling
• sample preparation
• sample portion selection
• Calibrators
• Reference material
• Input quantities
• Equipment used
• Environmental condition of sample and change of operators.
Proficiency testing
• Lab shall participate in EQAS/inter-laboratorycomparison as applicable.
• For those analytic where formal EQAS is not presentLab shall adopt method of inter laboratorycomparison with other NABL accredited lab
• For some rare analytes where such comparison isalso not possible then lab can ensure accuracy andprecision by replicate testing, examination of splitsamples, testing of retained samples.
where do I
start?!?
So much information …..
When 2 level QC Material are usedWhen 2 level QC Material are used
Levels of Comparison for Statistics
METHOD (Instrument)e.g.Glucose Oxidase on Hitachi 911
Method GROUPe.g. All Glucose Oxidase assays
ALL RESULTS or MODE
e.g. All Glucose methods
Example for Glucose:
If insufficient data for comparison
If insufficient data for comparison
Histogram
Your Result
Different shading is used to
identify Your Method, Your Group
and All Results
Levey-Jennings Chart
displays last 12 data points
The shaded boxes indicate the
comparator used for plotting the
Levey-Jennings and calculating
your Accuracy Score
Different symbols are used
to indicate a change in
comparator or late data
Look at the Accuracy Scores ( 0 – 10 )
A high score may need further investigation
Look for more information in
the “Summary of Your Results”
Accuracy Score
A measure of how close your result is to your comparator mean
On a scale of 0 – 10 (0 = ideal score, 10 = poor score)
Post examination procedures
• Authorized Signatures shall systematically review
the result of examination, evaluate them in
conformity with the clinical information.
• Storage of the primary samples as per policy and
safe disposal of samples
Reporting Results
• Format of report shall have unique identification, name of lab,name of patient & other unique identifier date & time ofcollection of sample & reporting.
• Result of examination with biological reference interval &interpretation of result where appropriate
• Lab shall establish critical limits of test which requireimmediate attention for patients management. Test results inthese limits shall be communicated to concerned person withproper documentation
• Biological reference interval should established by thelaboratory. If it is not possible lab shall carefully evaluate thepublished date for its own reference
Dr. Gajendra Gupta
ThanksDr. G.N.Gupta