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)

152

150

148

146

144

142

140

138

136

134

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