An overview over quality assurance program that are applied in the Department of Biochemistry.

1. Dipesh Tamrakar
M. Sc. Clinical Biochemistry

2. Overview
 Introduction
 Pre-analytical phase
 Analytical phase
 Post-analytical phase
 Tools of Quality Assurance
 Errors in laboratory

3. Introduction
 Quality control is one of the most scientific and
significant tool to correct errors in analytical
phase in the clinical laboratories.
 It is the procedures designed to monitor the
routine performance of testing processes in order
to detect possible errors, reduce and correct
deficiencies before the test results are reported.
 From Customer ‘s perspective, quality of a good
service for the price of the product
 The aim of quality control is simply to ensure
that the results generated by the test are correct.

4.  Quality Assurance - the overall program that
ensures that the final results reported by the
laboratory are correct.
 It is much more concerned with : that the right
test is carried out on the right specimen from the
right patient, and that the right result and right
interpretation is delivered to the right person at
the right time”
 Internal quality control (IQC) and external quality
assessment (EQA) programs are used to assess
and improve analytical performance.
Introduction

5.  IQC is self-assessing tool by using control
samples for the continuous and immediate
monitoring of the analytical part.
 IQC : to observe precise and accurate results on
daily analytical phase
 EQA is intended for periodic and retrospective
observing of laboratory results by an autonomous
external agency to specify to the laboratory about
the accuracy or bias in their systems methods and
results.
 EQA : to monitor long term accuracy and bias of
their results and stability of methods over a
longer period of time.
Introduction

6. Aims of Quality assurance
 Accuracy and precision
 Satisfactory
 Quality report
 Economical
 Aims at preventing defects rather than
detecting the defects
 Minimize errors
 Timely report

7. Quality Assurance vs. Quality Control
An overall
management plan
to guarantee the
integrity of data
(The “system”)
A series of analytical
measurements used to
assess the quality of
the analytical data
(The “tools”)

8. The Quality Assurance Cycle
•Data and Lab
Management
•Safety
•Customer
Service
Patient/Client Prep
Sample Collection
Sample Receipt
and Accessioning
Sample Transport
Quality Control
Record Keeping
Reporting
Personnel Competency
Test Evaluations
Testing

9. Few Terms:
Precision Accuracy
 The degree of
fluctuation in the
measurements
 The closeness of
measurements to
the true value
Quality Control is used to monitor both the
precision and the accuracy of the assay in order
to provide reliable results.

10.  Precise and inaccurate  Precise and accurate
Precision and Accuracy

11. Imprecise and inaccurate

12. Pre-analytical stage
• Test requisition slip
• Patient preparation
• Sample tube labeling
• Sample collection
• Sample
transportation
• Reagent storage
• Reagent preparation
• Quality control sera
storage
• Callibrator storage
• QC alliquet storage
• Quality monitoring
of refrigerator,
waterbath
• Maintenance and
cleaning of
instruments
Machine maintenance: Daily, Weekly, Monthly and
Annually

13. Analytical Stage
 Daily machine startup
 Daily Callibration: for Wet chemistry
 Daily Internal QC :
 Routine chemistry: BA 400 and Vitros 350
 CLIA: Diasorin for common test like TFT, aTPO
 Daily QC for i-Sens electrolyte analyzer
 Daily TDS measurement of DI water
•Lot wise callibration and QC of HbA1c in Hb Vario
•Weekly/monthly control of all uncommon tests in CLIA
•Callibration of Vitros 350 on change of reagent LOT

15. Selection of Control & Calibrators
 Has a known concentration of the substance
(analyte) being measured
 Used to adjust instrument, kit, test system in
order to standardize the assay
 Sources of QC samples:
 Appropriate diagnostic sample
 Obtained from:
 Another laboratory
 EQA provider
 Commercial product

16. Characteristics of a Good Control
 The composition of the control material should be
as similar to the patient sample as possible,
reacting in the same manner
 The analyte concentration should be at medically
significant levels
 Stable under storage for longer period of time
prior to preparation & even after prep
 Low vial-to-vial variability
 Requiring a minimum preparation or ready to use
 Reasonable in price

17. At DH-KUH
 For IQC: Callibrators:
 Dialab autocal
 Biosystem cal
 Reagent Pack Cal for
HbVario
 Reagent pack Cal for
Diasorin-CLIA
 Reagent Cartridge
cal for iSens
 Vitros Cal kit
 For IQC: Controls:
 Biorad
 Dialab controls
 Biosystem controls
 Reagent Pack Con
for HbVario
 Control Diasorin-
CLIA
 Mission control for
iSens
 PV for Vitros

18.  For EQAS: samples from
1. CMC Vellore, India
2. Chung-Ang University College of Medicine,
South Korea
3. NPHL, Nepal
At DH-KUH

19. Storage of QC Samples
 Controls are aliquoted into smaller ‘user friendly’
volumes for storage
 Establish a storage protocol:
 store at -20oC
 in use vials stored at 4oC
 use 0.5 ml vial maximum of one week

20. Monitoring QC Data
 Use Levey-Jennings chart
 Plot control values each run
 Acceptance of run
 Monitor precision and accuracy of repeated
measurements
 Review charts at defined intervals, take
necessary action, and document

21. Findings Over Time
 Ideally should have control values clustered about
the mean (+/-2 SD) with little variation in the
upward or downward direction
 Imprecision = large amount of scatter about the
mean. Usually caused by errors in technique
 Inaccuracy = may see as a trend or a shift,
usually caused by change in the testing process
 Random error = no pattern. Usually poor
technique, malfunctioning equipment

26. Westgard Rules
 “Multirule Quality Control”
 Uses a combination of decision criteria or control
rules
 Allows determination of whether an analytical run
is “in-control” or “out-of-control”
 Atleast run 2 control samples
12S rule R4S rule
13S rule 41S rule
22S rule 10X rule

27. Westgard – 12S Rule
 “warning rule”
 One of two control results falls outside ±2SD
 Alerts tech to possible problems
 Not cause for rejecting a run
 Must then evaluate the 13S rule
12S rule
violation

28. Westgard – 13S Rule
 If either of the two control results falls outside of
±3SD, rule is violated
 Run must be rejected
 If 13S not violated, check 22S
13S rule
violation

29. Westgard – 22S Rule
 2 consecutive control values for the same level
fall outside of ±2SD in the same direction, or
 Both controls in the same run exceed ±2SD
 Patient results cannot be reported
 Requires corrective action
22S rule
violation

30. Westgard – R4S Rule
 One control exceeds the mean by –2SD, and the
other control exceeds the mean by +2SD
 The range between the two results will therefore
exceed 4 SD
 Random error has occurred, test run must be
rejected
R4S rule
violation

31. Westgard – 41S Rule
 Requires control data from previous runs
 Four consecutive QC results for one level of
control are outside ±1SD, or
 Both levels of control have consecutive results
that are outside ±1SD
41S rule
violation

32. Westgard – 10X Rule
 Requires control data from previous runs
 Ten consecutive QC results for one level of control
are on one side of the mean, or
 Both levels of control have five consecutive
results that are on the same side of the mean
10x rule
violation

33. Westgard Multirule QC

34. When a rule is violated!!!!!
 Warning rule = use other rules to inspect the
control points
 Rejection rule = “out of control”
 Stop testing
 Identify and correct problem
 Repeat testing on patient samples and controls
 Do not report patient results until problem is
solved and controls indicate proper
performance

35. Types of Errors
Random=Fluctuations
Temperature
Personnel
Systematic
Reagent problem
Device problem

36. Solving “out-of-control” problems

37. Post-Analytical Stage
 Delta Check
 Report entry
 Report verification at 2 different levels
 Report print out
 Turn around time
 Emergency parameters: 1 hour
 Routine parameters: 2 hours
 Special immuno parameters: 2:30 hours

44. Sample storage for last 2 days at 4 degree C

45. Future plans:
 Sample bar coding
 Test requisition coding
 Reduce use of requisition form
 LIS to all department
 Full access of patient history and other
department finding via LIS