The document provides a comprehensive overview of quality control principles in clinical laboratories, covering definitions, objectives, and methodologies of quality management and assurance. It emphasizes the importance of total quality management (TQM) and continuous quality improvement (CQI) in achieving accurate and reliable test results, alongside external quality assessments. Additionally, it outlines the various variables affecting analytical processes and the critical role of documentation and staff training in maintaining laboratory quality standards.

1. “ QUALITY CONTROL IN CLINICAL
LABORATORY ”
Tapeshwar
Yadav
(Lecturer)
BMLT, DNHE,

2. OverviewOverview
• Definition of QualityDefinition of Quality
• Introduction to Quality ControlIntroduction to Quality Control
• Fundamentals of Quality ManagementFundamentals of Quality Management
• Total Quality ManagementTotal Quality Management
• Quality System And AssessmentQuality System And Assessment
• Quality Control & ImplementationsQuality Control & Implementations
• External Quality ControlExternal Quality Control
• New Quality InitiativesNew Quality Initiatives
2

3. Quality ?
 sum-total of all the characteristics
of a product/service that has a
bearing upon the utilization of the
product/service to the entire
satisfaction of the consumer
Conformance to the requirements of users
or customers and the satisfaction of their
needs and expectations
1) Acceptable
2) Accessible
3) Affordable
4) Appropriate3

4. Quality is....
• invisible whenGOOD
• impossible to ignore when
BAD
4

5. Introduction
• The issue of laboratory quality has evolved over more than
4 decades since the 1st
recommendation for quality control
were published in 1965
• Now, quality control is seen as only one part of a total
laboratory control program
• Quality also includes:
a) Total Quality Management (TQM)→ an activity to
improve pt. care by having the lab monitor, its work to
detect deficiencies & subsequently correct them
5

6. b) Continuous Quality Improvement (CQI) or
Performance Improvement (PI)→ to improve the pt. care
by placing the emphasis on not to make mistakes in the
first place
c) Quality Assurance (QA)→ external activities that
ensure positive pt. outcomes. It measures what a lab can
do to improve reliability
6

7. Fundamentals of Quality Management
Principles of Quality management, assurance, and control
have become the foundation by which clinical laboratories
are managed and operated
• Total Quality Management of clinical Laboratory
• Control of pre-analytical variables
• Control of analytical variables
• External quality assessment & Proficiency testing
programs
7

8. Total Quality Management
• TQM also referred to as :
total quality control (QC), total quality leadership,
continuous quality improvement, quality management
science or industrial quality management
• Quality systems in healthcare organization is evolving
• Public & Private pressure to contain costs are now
accompanied by pressure for quality improvement (QI)
• TQM provides – management philosophy for
organizational development & a management process for
improvement of quality in all aspects of work
8

9. • The Universal principles of TQM are
(1) Customer focus
(2) Management commitment
(3) Training
(4) Process capability & control
(5) Measurement using quality-improvement tools
• Costs must be understood in the context of quality
• Quality = conformance to requirements
• “Quality costs”
Concepts of TQM
9
=“Costs of conformance” + “Costs of non
conformance”

10. Quality Costs
Costs of
Conformance
Costs of
Nonconformance
Prevention
Costs
Appraisal
Costs
External
failure Costs
Internal
failure Costs
Examples:
Training
Calibration
Maintenance
Examples:
Inspection
Quality control
Examples:
Scrap
Rework
Repeat runs
Examples:
Complaints
Service
Repeat request
Understanding of quality & cost leads to a new perspective of relationship b/n
these two concepts:
“ Improvement in quality lead to reduction in costs”
10

11. Methodology
• Quality improvement occurs when problems are eliminated
permanently
• Quality problems are primarily management problems
because only management has the power to change work
process
• TQM views the organization as a support structure rather
than a command structure
• Most immediate processes required for the delivery of
services are those of the frontline employees
• Senior management’s role is to support the frontline
employees & empower them
11

12. 12

13. • QLPs - include analytical processes & the general policies ,
practices, and procedures that define how all aspects of the
work are done
• QC- emphasizes statistical control procedures, but also
includes nonstatistical check procedures
• QA- concerned primarily with broader measures &
monitors of lab performance (turnaround time, specimen
identification, patient identification, test utility)
• QI- a structured problem solving process to help identify
the root cause of a problem & a remedy for that problem
• QP- provides the planning steps
Implementing TQM
13

14. These five components, which work together in a feedback loop,
illustrate how continuous QI is accomplished and quality assurance is
built into laboratory process
14

15. “Five –Q” framework also defines how quality is managed
objectively with the “scientific method”, or the PDCA cycle
QP-provides the planning step, QLP- establishes standard processes, QC & QA
provide measures for checks and QI provides a mechanism through which to act on
those measures
15

16. • TQM is also considered as a quality system that is
implemented to ensure quality
• QS- “ set of key quality elements that must be in place for
an organization’s work operations to function in a manner
to meet the organization’s stated quality objectives”
16

17. Quality Systems
 The main objective of a laboratory is to
provide reliable, timely and accurate test
results. This is only possible through
 consistent monitoring and evaluation of the
laboratory’s performance
 the implementation and follow-up of corrective
actions for non-conformance to procedure
17

18. Quality Systems
• A reputation based on 10,000 good quality results is
damaged by 1 poor quality result
• The establishment of robust testing systems is
essential to the success of laboratory services and
the treatment program
• The establishment and continuous monitoring of
quality systems in each testing laboratory is required
for reliable and robust testing
18

19. Quality Systems
• Provide the assurance of the quality of the test
results
• Ensure that the lab operations are coordinated,
organised and standardised
• Are tools to monitor performance
19

20. • QUALITY ASSESSMENT (EXTR.)
QUALITY: A DEGREE OF EXCELLENCE
• QUALITY CONTROL (INTER.)
++
QUALITY ASSURANCEQUALITY ASSURANCE
20

21. Quality Procedures
• Internal Quality Control (IQC)
– includes personnel, instrumentation, document
control, reagent control and corrective action
• External Quality Assurance (EQA)
– External quality control is important to ensure
the laboratory is performing to an external
standard
21

22. Assessment of Quality System
• Audit, On-site
inspection
• Internal
• External
• Accréditation
Man-driven Material-driven
• Quality Assessment
• Internal
• External
• Schematic way:
External Quality As
sessment Scheme (
EQAS)
22

23. QC v/s QA
• Quality Control -QC refers to operational
techniques that must be included during each
assay run to verify that the requirements for
Quality are met with
• Quality Assurance - QA refers to all those planned
and systematic activities to provide confidence
that the results given out by the laboratory are
correct
The aim of QC is simply to ensure that the results generated by the
test are correct. However quality assurance is concerned with much
more: that the right test is carried out on the right specimen and that
the right result and right interpretation is delivered to the right
person at the right time
23

24. QUALITY ASSURANCE (QA)
• The purpose of QA is the maintenance of the overall
quality of patient results
• All factors that effect the test results from the time
the test
Pre-analyticPre-analytic AnalyticAnalytic Post-analyticPost-analytic
Specimen collectionSpecimen collection
Specimen transportSpecimen transport
Specimen qualitySpecimen quality
Result accuracyResult accuracy
Clerical errorsClerical errors
Analytical errorsAnalytical errors
Assay repeat ratesAssay repeat rates
Result reportingResult reporting
Record keeping forRecord keeping for
patient and QCpatient and QC
24

25. 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 EvaluationsTesting
25

26. Quality Control & ImplementationQuality Control & Implementation

27. Quality control
• Quality control is a vital part of quality assurance
– All labs benefit from quality control in terms of confidence in
and reproducibility of test results
• Recording and monitoring test variables such as
temperature, reagents, controls and equipment
function allows one to look objectively and
retrospectively at parameters vital to the accuracy and
precision of the test
• Documentation allows one to foresee a potential
problem before the situation requires corrective action
and adversely effects patient results
27

28. Quality in labs is mutual responsibility of…..
• Laboratory specialists
• Clinicians
• Public health physicians
28

29. Objectives of quality in labObjectives of quality in lab
• Support provision of high quality health-care
– Reduce morbidity
– Reduce mortality
– Reduce economic loss
• Ensure credibility of lab
• Generate confidence in lab results
29

30. Consequences of poor qualityConsequences of poor quality
• Inappropriate action
– Over-investigation
– Over-treatment
– Mistreatment
• Inappropriate inaction
– Lack of investigation
– No treatment
• Delayed action
• Loss of credibility of laboratory
• Legal action
30

31. How to implement a QC program?How to implement a QC program?
– Establish written policies and procedures
– Assign responsibility for monitoring and reviewing
– Train staff
– Obtain control materials
– Collect data
– Set target values (mean, SD)
– Establish control charts, Eg- Levey-Jennings charts
– Routinely plot control data
– Establish and implement troubleshooting and corrective action
protocols

32. Hurdles in Quality Control
• Accurate & timely test report are the responsibility of the
laboratory
• Total testing process must be managed properly in the
preanalytical, analytical, and postanalytical places
32

33. Control of Preanalytical Variables
Preanalytical variability is defined as errors which occur
when non-analytical factors change the conc. of analytes
• Test conducted- appropriate test should be requested &
performed
• Patient identification- labeling of specimen may be
improper; corrected by bar coding
• Turnaround time (TAT)-should be kept minimum
• Laboratory logs- entry of patient & test details in lab
registers & computers
• Transcription errors- a substantial risk of transcription
error exists from manual entry of data, even when results
are double checked; computerization reduces this error
33

34. • Patient preparation- proper patient preparation is
essential to obtain meaningful test result
• Specimen collection- container, anticoagulant, time taken
to send specimen to lab, corrected by using vacutainer
tubes & collection of samples by lab personnel
• Specimen Transport- critical for some tests
• Specimen Separation, aliquoting- monitoring of the
performance of the centrifuge, container used for storage
• Personnel- variation fr person to person. Safety
precautions for all specimens. Throughput time to be
monitored on a weekly or monthly basis
Control of Preanalytical Variables
34

35. Factors influencing analytical variables
EQUIPMENT RELIABILITY:
Meet technical needs, Compatible, User
& maintenance friendly, Cost effective,
Validated
Procedural
reliability using
Standard Operating
Procedures
REAGENTS STABILITY, INTEGRITY AND
EFFICIENCY:
Stable, Efficient, Desired quality,
Continuously available, Validated
SPECIFICITY & SENSITIVITY
OF SELECTED TEST:
Adequate ST, Sufficient SP,
cost effective, compatible
with, available infrastructure
and expertise, interpretable,
meets the needs/ objectives,
validated
PROFICIENCY OF PERSONNEL:
Education, Training, Aptitude,
Competence, Commitment,
Adequate number, CME,
Supervision, Motivation
USE OF APPROPRIATE
CONTROLS:
• Internal: Labs, Calibrated against
national
• External: Supplied by
manufacturer, National,
International
DOCUMENTATION:
All the written policies, plans, procedures,
instructions and records, quality control
procedures and recorded test results involved
in providing a service or the manufacture of a
product
Assessment
ANALYTICAL FACTORS
35

36. • Analytical variables must be controlled carefully to ensure
accurate measurements by analytical methods
• Reliable analytical methods are obtained through careful
process of :
(1) Selection
(2) Evaluation
(3) Implementation
(4) Maintenance
(5) Control
• Clear concepts in relation to Analytical methods-
Calibration, trueness, accuracy, precision, linearity, & limit
of detection
Control of Analytical Variables
36

37. CalibrationCalibration
• The calibration function is the relation between instrument
signal(y) and conc. of analyte (x)
y=f(x)
or, x=f1
(y)
• It is set of operations that establish the relationship
between values of quantities indicated by the instrument
and the corresponding values realized by ”measurement
standards”
• Calibration function may be linear or curved graphically
• In automated clinical chemistry instruments , the relation
b/n analyte conc. and signal is often very stable
• In traditional chromatography (HPLC), it is customary to
calibrate each analytical run 37

38. TruenessTrueness
• Trueness of measurements- closeness of agreement b/n
the average value obtained from a large series of results of
measurements and a true value
• True value- The known, accepted value of a quantifiable
property
• Bias- The difference b/n average value & the true value
• Measured value- Result of an individual’s measurement of
a quantifiable property
38

39. AccuracyAccuracy
• Accuracy- the closeness of the agreement b/n
the result of a measurement & a true conc. of
the analyte
39

40. PrecisionPrecision
• Precision- closeness of agreement b/n independent
results of measurements obtained under stipulated
conditions
• It is the dispersion of replicate measurementsIt is the dispersion of replicate measurements
• Inter-assay with multiple runsInter-assay with multiple runs
• Intra-assay: within a runIntra-assay: within a run
40

41. PrecisionPrecision
• Repeatability (within same run)
• Reproducibility or closeness of results to each other
performed under changed conditions of measurement
(time,operator,calibrators, reagent lots)
– Measured by the standard deviation or coefficient of
variation
• Std. dev (σ)/mean(X) x 100 = % C.V.
41

42. ReliabilityReliability
• The ability to maintain both precision and accuracy
42

43. LinearityLinearity
• Linearity refers to the relationship between measured &
expected values over the analytical measurement range
• May be considered in relation to actual or relative analyte
concentration
• Evaluated by plotting measured& expected conc., F-test,
regression analysis of test run
• Testing of linearity is related to assessment of trueness
over the analytical measurement range
• The presence of linearity is a prerequisite for a high degree
of trueness
43

44. Limit of Detection & QuantificationLimit of Detection & Quantification
• Limit of blank (LoB): highest measurement result that is
likely to be observed for a blank sample
• Limit of Detection (LoD): lowest concentration of
measurand that can be consistently detected in ≥ 95% of
samples tested under routine laboratory conditions and in
a given sample matrix
• Limit of Quantification (LoQ): lowest actual amount of
analyte that can be reliably detected and at which the total
error meets the laboratory’s requirements for accuracy
The distinction b/n different results interpretations is
dependent on the relationship b/n LoQ, LoD and LoB
“detected” “detected but below LoQ” “not detected” 44

45. Variables that may cause imprecisionVariables that may cause imprecision
• EquipmentEquipment
– Multiple instrumentsMultiple instruments
– Pipettes – check precisionPipettes – check precision
– Sporadic maintenanceSporadic maintenance
• ReagentsReagents
– Different Lots of Reagents lot-to-lot evaluationDifferent Lots of Reagents lot-to-lot evaluation
• StaffStaff
– Difference in training, competenciesDifference in training, competencies
45

46. Laboratory EquipmentLaboratory Equipment
• All equipment in the laboratory
– Should have instruction manuals regarding proper
use and maintenance requirements
– Should be monitored and recorded for quality
control procedures, function checks, preventative
maintenance and repairs
• These should be documented and filed in separate log
books
￫46

47. Laboratory EquipmentLaboratory Equipment
• Before putting new equipment or a new method into
service – it must be validated
- This is accomplishment by correlation and/or agreement
studies
- The new method or equipment is validated against old
method and/or equipment
• Refrigerators and freezers
- Record serial numbers
- Record temperatures daily
Maintaining correct temperatures is vital to
maintaining the integrity of reagents and should be
maintained as per manufacturers’ instructions.
47

48. Instrument MaintenanceInstrument Maintenance
• CONTROLS and CALIBRATORSCONTROLS and CALIBRATORS
Manufacturers can provide calibrators and internal controls
• REGULAR MAINTENANCEREGULAR MAINTENANCE
– Daily and weekly instrument maintenance
– Monthly, six-monthly and annual maintenance as recommended by
supplier
• ROUTINE MAINTENANCEROUTINE MAINTENANCE
Ensure that instruments are serviced regularly by a specialised
service engineer and that this maintenance is documented
48

49. Instrument MaintenanceInstrument Maintenance
Required for:
•Producing reliable test results
•Minimizing instrument breakdown
•Lowering repair costs
•Preventing delays in reporting test results
•Maintaining productivity
•Lengthening instrument life
49

50. PIPETTE’S IMPACT ON QCPIPETTE’S IMPACT ON QC
•Pipette accuracy and precision must checked regularly -
the first time of use and periodically thereafter
•If either fails, it is important to follow the manufacturer’s
instructions for repair and calibration
• Improperly calibrated pipettes will affect our assay and
should be checked for precision and accuracy bi-annually
50

51. PIPETTE’S IMPACT ON QCPIPETTE’S IMPACT ON QC
• Pipettes not passing accuracy checks should be cleaned
and checked for worn parts, and be sent to and
serviced by reliable vendors
• Maintain complete records of pipette calibration function check
– Include serial and other identifying numbers of each pipette
51

52. Reagents in LaboratoryReagents in Laboratory
• How to store reagents
– Always store according to the manufacturer’s
recommendations
– Reagents must be dated and initialed upon receipt
– Lot numbers must be recorded in a reagent quality
control record book
– After preparation and/or when placed in service,
reagents must be labeled when put “in service”
according to the manufacturer’s suggested
recommendations
￫52

53. • Reagent parallel testing
– New reagent lots must be checked with old lots using
a normal control before use
– The variability for new lots of reagents compared to
the current lot should not be greater than the
variability found for triplicate samples of the current
lot
– Variability should be within 5%
– Results of reagent checks must be recorded, dated
and initialed
– Document all lot to lot procedures with date and
variability results
Reagents in LaboratoryReagents in Laboratory
53

54. • Restrict all testing procedures to staff with
appropriate technical training
– Testing theory
– Instruments
– Testing procedures
• Perform and document periodic performance
assessments on all testing staff
PERSONNEL (Staff)PERSONNEL (Staff)
54

55. PERSONNEL (Staff)PERSONNEL (Staff)
 Active participation by everyone working in the
system is required to meet quality standards &
continuously improve performance
 It is laboratory director's responsibility to employ
sufficient qualified personnel for the volume and
complexity of the work performed
 Continuing education program should be provided
 All documentation should maintained in personnel
file
 Regular meeting to keep staff informed of changes &
to solicit their suggestion for improving the lab.
service
55

56. DocumentationDocumentation
• If you have not documented it,If you have not documented it,
you have NOT done it …you have NOT done it …
• If you have not documented,If you have not documented,
it is a RUMOUR !!!it is a RUMOUR !!!
56

57. Value of DocumentationValue of Documentation
• Ensures processes and outcomes are traceableEnsures processes and outcomes are traceable
• Processes can be audited, thus externalProcesses can be audited, thus external
assessments can take placeassessments can take place
• Tool for trainingTool for training
• Reminds what to do nextReminds what to do next
57

58. Key DocumentsKey Documents
• Results archive
– File results in an organised and easily accessible manner
• Laboratory monitoring
– Documentation of temperature monitoring, reagent
control, accuracy/precision assays, corrective actions,
audit reports
• Instrumentation
– SOPs
– Equipment files + Manuals
– Service history records of the instrument
– Records of daily, weekly and monthly calibrations and
maintenance 58

59. Standard Operating ProceduresStandard Operating Procedures (SOP)(SOP)
• comprehensively writtencomprehensively written
document that describes thedocument that describes the
laboratory procedure and alllaboratory procedure and all
other related issuesother related issues
• Essential for ensuringEssential for ensuring
uniformity in laboratoryuniformity in laboratory
proceduresprocedures
SOP for
TFT
•The SOP should define test performance, toleranceThe SOP should define test performance, tolerance
limits, reagent preparation, required quality control,limits, reagent preparation, required quality control,
result reporting and referencesresult reporting and references
59

60. • The SOPM should be written in CLSI format and
must be reviewed and signed annually by the
Laboratory director
• Must contain all test methods performed by the
laboratory
• The SOPM should be available in the work area. It is
the definitive laboratory reference and is used often
for questions relating to individual test
• Any obsolete procedures should be dated when
removed from SOPM and retained for at least 2
years
60

61. Outline for aOutline for a CLSICLSI ProcedureProcedure
DocumentDocument
A. Title: intent of the document; concise
B. Purpose or Principle: “the process describes..” info.
regarding theory, clinical implications of examination
C. Procedure instruction: “how to do” a particular steps,
steps involved
D. Related Documents: listing of other procedures used
E. References: reference the source of information
F. Appendixes or attachments: additional information
G. Author(s): author of the document should be
documented
H. Approved Signature: Evidence that the document has
been approved
61

62. ValidationValidation
 is about determining whetheris about determining whether
something does what it is supposedsomething does what it is supposed
to doto do
62

63. Importance of validationImportance of validation
• Validation - before we introduce somethingValidation - before we introduce something
• Re-validationRe-validation
– after we have changed/modifiedafter we have changed/modified
– periodicperiodic
• Validation is applied to:Validation is applied to:
– SOPSOP
– reagentsreagents
– equipmentequipment
– softwaresoftware 63

64. Factors influencing quality:Factors influencing quality:
Post-analyticalPost-analytical
• Right recording and reportingRight recording and reporting
• Right interpretationRight interpretation
– Range of normal valuesRange of normal values
• Right turnaround timeRight turnaround time
• Report to right userReport to right user
64

65. Reporting resultsReporting results
• Proper procedure includes:
– All data entry results should be verified by a section
head or supervisor (when available) and reviewed
by management for final interpretation and release
of results
– In the event that a report has already been sent out
and needs correction, a new report is issued with
updated report written on it
• The old report remains in the patient file
– Verbal result reports should be documented, listing
the time of the receipt of the report
65

66. HousekeepingHousekeeping
• Surface decontamination of instruments, benchtops,
biosafety hoods and general tidiness
• Disposal of biohazardous waste
• Monitoring of fridge, freezer and incubator
temperatures
66

67. Statistical Control of Analytical
Methods
• Statistics definitions :
- Mean, Mode, Median, Standard Deviation
- Coefficient of Variation (CV) is the ratio of the SD to the
average. It is a measure of relative precision expressed as
percentage
• Reference ranges :
As per IFCC recommendations, reference values are based
on that of a reference individual, it is established in healthy
individuals based on application of statistical methods to
values generated in the lab
67

68. Reference rangesReference ranges
• What do I do when controls are out of established
reference ranges?
– Results of the normal donor control are expected to be
within the established reference range. If results exceed
reference range limits, follow corrective action:
• Repeat test using same aliquot
• If the results still exceed the limits, do not automatically
invalidate patient results
– Due to the 95% confidence interval, 1 in 20 specimens from healthy
individuals drawn at random can be outside reference range limits
due to biological factors
68

69. Control Materials
• Specimens that are analyzed for QC purpose are known as
control materials
• Control materials should be available :
-in a stable form
-in aliquots or vials
-for analysis over an extended period of time, at least 1 yr
• Minimal vial-to-vial variation should exist
• Should have preferably the same matrix as the specimen
69

70. Types of Control MaterialsTypes of Control Materials
• Assayed
– mean calculated by the manufacturer
– must verify in the laboratory
• Unassayed
– less expensive
– must perform data analysis
• “Homemade” or “In-house”
– pooled sera collected in the laboratory
– characterized
– preserved in small quantities for daily use
70

71. Managing Control MaterialsManaging Control Materials
• Sufficient material from same lot number or serum pool
for one year’s testing
• May be frozen, freeze-dried, or chemically preserved
according to instructions by the manufacturer
• Requires very accurate reconstitution if this step is
necessary
• Always store as recommended by manufacturer
71

72. CalibratorsCalibrators
• Has a known concentration of the substance
(analyte) being measured
• Used to adjust instrument, kit, test system in order
to standardize the assay
• Sometimes called a standard, although usually not a
true standard
• This is not a control
72

73. Control Charts
• A common method to compare the values observed for
control materials with their known values is the use of
control charts
• Simple graphical displays in which the observed values are
plotted versus the time when the observations are made
• Known values are represented by an acceptable range of
values
• When plotted points falls within the control limit- method
is performing properly
• When points falls outside control limit – problem may be
developing 73

74. LEVY- JENNINGS GRAPHLEVY- JENNINGS GRAPH
L-Js are the process control graphs wherein the daily
Q.C. values for all levels of controls are plotted
(minimum 20 values) and an inference about the run is
drawn , to decide “in control” or “out of control run.”
Advantage:
•Simple data analysis and display
•Easy adaptation and integration into existing control
practices
•A low level of false rejection or false alarms
•An improved capability for detecting systematic and
random errors
74

75. LEVEY - JENNINGS GRAPHLEVEY - JENNINGS GRAPH
• It should be automatically generated for the
parameters chosen in a QC template
• Should be available for viewing by day,
month, and other fractions of the year
• Use limit criteria either calculated from the data, or
from user defined means and SDs
• Use red for data points that are outliers
75

76. LJ CHART PLOTTED : AN EXAMPLELJ CHART PLOTTED : AN EXAMPLE
76

77. Westgard RulesWestgard Rules
(Generally used where 2 levels of control
material are analyzed per run)
• 12S rule
• 13S rule
• 22S rule
• R4S rule
• 41S rule
• 10X rule
77

78. Westgard – 1Westgard – 12S2S RuleRule
• 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
78

79. 112S2S RuleRule = A warning to trigger careful inspection= A warning to trigger careful inspection
of the control dataof the control data
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
12S rule
violation
79

80. Westgard – 1Westgard – 13S3S RuleRule
• If either of the two control results falls outside of
±3SD, rule is violated
• Primarily sensitive to random error
• Run must be rejected
• If 13S not violated, check 22S
80

81. 113S3S RuleRule = Reject the run when a single control= Reject the run when a single control
measurement exceeds the +3SD or -3SD control limitmeasurement exceeds the +3SD or -3SD control limit
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
13S rule
violation
81

82. Westgard – 2Westgard – 22S2S RuleRule
• 2 consecutive control values for the same level fall
outside of ±2SD in the same direction
• Sensitive to systematic error
• Patient results cannot be reported
• Requires corrective action
82

83. 222S2S RuleRule = Reject the run when 2 consecutive control= Reject the run when 2 consecutive control
measurements exceed the samemeasurements exceed the same
+2SD or -2SD control limit+2SD or -2SD control limit
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
22S rule
violation
83

84. Westgard – RWestgard – R4S4S RuleRule
• 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
84

85. RR4S4S Rule = Reject the run when 1 controlRule = Reject the run when 1 control
measurement exceed the +2SD and the othermeasurement exceed the +2SD and the other
exceeds the -2SD control limitexceeds the -2SD control limit
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
R4S rule
violation
85

86. Westgard – 4Westgard – 41S1S RuleRule
• Requires control data from previous runs
• Four consecutive QC results for one level of control
are outside ±1SD
• Sensitive to systematic error
86

87. Westgard – 10Westgard – 10XX RuleRule
• Requires control data from previous runs
• Ten consecutive QC results for one level of control
are on one side of the mean (above or below, with
no other requirement on the size of deviation)
• Sensitive to systematic error
87

88. 1010xx RuleRule = Reject the run when 10 consecutive control= Reject the run when 10 consecutive control
measurements fall on one side of the meanmeasurements fall on one side of the mean
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
10x rule
violation
88

89. External Quality Assessment
• All the control procedures described previously have
focused on monitoring of a single lab
• These procedures constitute internal QC, to distinguish
them from procedures used to compare the
performance of different laboratories are known as
external Quality assessment
• These two procedures are complimentary
• Internal QC- daily monitoring of precision & accuracy
• External QA- long term accuracy of analytical methods
89

90. • EQA results evaluate performance of the laboratory
against other laboratories participating in the same
program
• Different programs do this in different ways. Eg, t-test is
used to test the statistical significance of any difference
b/n an individual lab’s observed mean & the group mean
• When the diff. is significant lab. is alerted
• Results are instrument and protocol specific
• EQA results should be formally documented within the lab
and should be available on request
External Quality Assessment
90

91. • In India EQA is done by Govt. / private organizations
- National Accreditation Board for Testing &
Calibration Laboratories (NABL) , Dept. of Science &
Technology,GOI.(http://www.nabl-india.org)
- ACBI-CMC External Quality Assurance Scheme,
Christian Medical College, Dept. of Clinical
Biochemistry, Chennai(http://www.cmcvellore.ac.in)
External Quality Assessment in India
91

92. Proficiency testingProficiency testing
• Laboratories should all enroll and satisfactorily
participate in a performance evaluation/assessment
program
– If conventional proficiency testing is not available, the
laboratory must exercise an alternative performance
assessment system for determining the reliability of
analytic testing (sample splitting for inter-laboratory
testing)
– If the lab has more than one method-system for
performing tests for an analyte, it must be checked
against each other at least twice a year for correlation
of patient results 92

93. New Quality Initiatives
• Several new quality initiatives have been developed &
implemented to ensure that labs incorporate the
principles of Quality Management & QA in daily operation
- Six Sigma process
- Lean Production
- ISO 9000
- Joint Committee for Traceability in Laboratory Medicine
(JCTLM) Guidelines.
93

94. 94
To ensure that a laboratory practices and provides
quality assurance for all phases of testing, the
laboratory should:
Enroll and satisfactorily participate in a performance
evaluation/assessment program
Establish reference ranges for analytes being tested
Document training and competency assessment for
their technicians
Provide review and verification of all results released,
including verbal result reports
￫
SUMMARY

95. SUMMARY
• Quality control is a part of a total laboratory control
program under Total Quality Management
• TQM is responsible for organizational development and
management for improved quality in all aspects
• Five Qs- Qlp,QC,QA,QI,QP constitute the TQM
framework
• Quality Control is achieved through proper documented
and validated interventions at Preanalytical, analytical
and post analytical stages
• Quality Assurance is internal Quality assessment plus
external Quality assessment
X 95

96.  No matter how good the quality system is on
paper, quality cannot be achieved if the theory
cannot be translated into practice
Quality costs,
but poor quality costs more …
96

97. References
• Teitz Fundamentals of Clinical Chemistry,6th
Ed.
• Harold Varley 4th
Ed.
• Bailey & Scott’s 12th
Ed.
• Internet
97

98. Thank You
98