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ISSUES OF CLINICAL LABORATORY QUALITY ASSURANCE PROGRAMME IN PAKISTAN Brig (R) Dilshad Ahmed Khan SI (M) Professor of Pathology NUMS, Rawalpindi. Quality Assurance Programme.
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ISSUES OF CLINICAL LABORATORY QUALITY ASSURANCE PROGRAMME IN PAKISTAN Brig (R) Dilshad Ahmed Khan SI (M) Professor of Pathology NUMS, Rawalpindi
Quality Assurance Programme • Quality Control - The aim of quality control is simply to ensure that the results generated by the test are correct & verify that the testing system is working properly. • Quality Assurance - Ensures that the final results reported by the laboratory to the patient are correct: that the right test is carried out on the right specimen, right interpretation/result is delivered to the right person at right time
Factors That Affect Quality of Patient’s Results • The condition of the specimens • Reagents & Equipment • Internal quality controls program • Participation in external quality program • The interpretation & reporting of results
Unreliable QA Program ? Potential consequences of unreliable QA Performance include:- • Patient misdiagnosis • Delays in treatment • Increased costs
QA Performance Failure • Pre-analytical:- • Errors before the sample reaches the laboratory • Analytical:- • Errors during the analysis of the sample • Post-analytical:- • Errors occurring after the analysis
Pre – Analytical Issues Sample Collection Incorrect specimen storage Sample Transport Sample haemolysis/ Incorrect specimen container Sample left overnight at room temp/ long term storage at 4c • Delay in samples delivery/Temperature
Improper Collection of Blood Samples • Sample haemolysis • LDH, potassium or inorganic phosphate • Effects of exercise • creatinekinase / CRP • Collection timing • 24 hour urine
Incorrect Specimen Container • Serum or plasma • PTH, ACTH • Fluoride tubes for glucose • to inhibit glycolysis • EDTA tube • Unsuitable for calcium assay
Incorrect Specimen Storage • Sample left overnight at room temperature • Falsely elevated K, Pi and red cell enzymes • short –term refrigeration • medium term freezing at –20oC • long term freezing at -80oC • Delay in sample delivery • Falsely lowered levels of unstable analytes
Internal Quality Control • Daily running of two control sera • Calculation of their mean and standard deviation • Plotting them on control charts • Daily checking and Interpretation of graphs
Example Mean result (x) = 100 mmol/L Standard deviation (SD) = 1.0 mmol/L Number of results (n) = 100
Mean +/- 1SD x -1SD +1SD Values fall randomly about a mean value. 68% Frequency 99 100 101
Mean +/- 2SD x -2SD +2SD Values fall randomly about a mean value. 95% Frequency 98 100 102
Accuracy ? How correct your result is.
Precision ? The reproducibility of your results.
Which is more Precise ? Performing better ? Potassium mean 5 ; SD = 0.1 mmol/L Sodium mean 140; SD = 2.0 mmol/L
Example Sodium has the better CV and in this example is performing better than potassium. Potassium %CV = (0.1 / 5.0) x 100% = 2.0% Sodium %CV = (2.0 / 140) x 100% = 1.4%
Westgard Rules • Westgard provides multiple QC rules: • Defines acceptability of analytical process • minimises false rejections • maintains high error detection
Levey Jennings Chart +2SD 143 +1SD 141.5 X X X X X X X Mean X 140 X X X X X X X -1SD 138.5 X X -2SD 137
Levey Jennings Chart +2SD 143 X X X +1SD 141.5 X X X X X Mean X 140 X X X X -1SD 138.5 X X X X -2SD 137
Levey Jennings Chart +2SD 143 141.5 +1SD X X X X X X X X X X Mean 140 X X X X X X X -1SD 138.5 -2SD 137
Levey Jennings Chart 143 +2SD X X X +1SD X 141.5 X X X X X X X X X X X X X Mean 140 -1SD 138.5 -2SD 137
Shift ? Inaccurate calibration/recalibration Sudden failure or change in the light source Change in reagent formulation Change of reagent lot Sudden change in incubation temperature (enzymes ) Failure in the sampling system Failure in reagent dispense system
Levey Jennings Chart? 143 X +2SD X X X +1SD X 141.5 X X Mean 140 X X X 138.5 X -1SD X X X X -2SD 137 X X
Trend ? • Gradual deterioration of control materials • Deterioration of the instrument light source • Gradual accumulation of debris in sample/reagent tubing • Aging of reagents • Gradual deterioration of incubation chamber • Gradual deterioration of light filter integrity
External Quality Assurance? Proficiency testing is thesystem designed to objectively assess the quality of results obtained by laboratories, by means of an external agency.
Benefits of EQA Provide an inter-laboratory comparison Allows participants to identify problems with their testing process (Accuracy) Investigate factors in performance of tests (methods, Instrument, Reagents etc) Supplement internal quality control procedures Identifies improvement opportunities
External QA Programme • International • Regional • National
International External QC • REQAS (Rs 75,000/year) • BIORAD (Rs 80000/year) • CAP (Rs 100000/year)
National External Quality Assurance Programme in Pakistan • E Q A pre-requisite for any country • Designed specifically for the country’s needs • Economical (NEQAPP Rs 2000/year) • Useful in establishing national quality goals • Fulfilling the requirement of accreditation by PNAC
NEQAPP • Clinical chemistry PT programme Started in 1996 • 60 labs invited for the scheme • 47 labs enrolled • Each lab allotted a confidential code number • QC sera sent every three months • Results
List of Analytes • Albumin • Bilirubin • Cholesterol • Creatinine • Glucose • Lithium • Magnesium • Osmolality • Inorganic phosphate • Potassium • Total protein • Sodium • Triglycerides • Urea • Uric acid • Acid Phosph. (Total) • ALT • AST • Alkaline phosphatase • Amylase • CK • LDH
Cumulative statistics: Percentage bias Percentage Inorganic PO4 Glucose
EQA: Causes of Poor Performance • Methodological/reagents reasons (33%) • Technical/intruments reasons (19%) • Clerical reasons (12%) • Blunders (11%) • Un-explained reasons (25%)
Expand Scope of NEQAPP • Expand NEQAPP to all disciplines of Pathology • Funding for necessary infrastructure • Enhance QA of labs on national level
PC-1 for NEQAPP • Submitted in early 2005 • Prepared By: • Brig Dilshad Ahmad Khan • Checked By: • Brig Farooq Ahmad Khan • Approved by: • Maj Gen Masood Anwar, HI(M)
PC-1 for NEQAPP • Team of PNAC visited AFIP • PNAC requested Surg Gen for cooperation • Sectoral committee of PNAC for clinical labs • PC-1 for NEQAPP was approved in 2009
Expand NEQAPP Programme offered in 2010 Clinical Chemistry Immunoassay/ Tumour Marker Haematology Microbiology Histopathology
New Participants 1 Questionnaire EQAS Process 2. Preparation of Panels 3. Panel Distribution 4. Data Collection 5. Data Analysis 6. Final Report
Enrollment Documentation ENROLMENT DOCUMENT: - To be returned to NEQAPP, AFIP Rawalpindi With Following Information: LAB NAME PATHOLOGIST ADRESS E-MAIL TELEPHONE NO PROGRAMME When the details have been entered in the enrolment document it should be sent to NEQAPP, AFIP or Register on website for registration (www. Neqapp.net)
Pre-requisites- NEQAPP • List of analytes • Methods • Instruments/equipments • Reagents
PT Samples • Lyophilized human serum • Similar to patient specimens • Appropriate concentration levels • Good long term stability • Easy to transport • Reconstitution errors
General Chemistry Program : Specimen Design High Pool Specify lowest and highest specifications 4 Level 6 3 + High Pool Low Pool 2 1 Lyophilized human serum Low Pool Level 1