Quality in Biochemistry Laboratory
Dr Farideh RaziMD.AP.CP*
The Quality Assurance CycleData and Lab ManagementSafetyCustomer ServicePatient/Client PrepSample CollectionSample Receipt and AccessioningSample TransportQuality ControlRecord KeepingReportingPersonnel CompetencyTest EvaluationsTesting
Right resultRight specimenRight patientRight timeRight price
*Quality Assurance TargetPre AnalyticAnalyticPost Analytic
Test orderingInappropriate testHandwriting not legibleWrong patient identificationSpecial requirements not specifiedCost or delayed order
Specimen acquisitionIncorrect tube or containerIncorrect patient identificationInadequate volumeInvalid specimen (e.g., hemolyzedor too dilute)Collected at wrong timeImproper transport conditions
Test reportingWrong patient identificationReport not posted in chartReport not legibleReport delayedTranscription error
Test interpretationInterfering substances not recognizedSpecificity of test not understoodPrecision limitations not recognizedAnalytical sensitivity not appropriatePrevious values not available forcomparison
Control Of Analytical Variable
Limit check
1 A 1 2 .
97 94 93 97 96 93 89 88 79 86 98 89 87 76 79 97 95 98 88 89
143 143 154123 127 153 124 132 143 126 145 150 127 128 148 150 145 130 142 129
*
*
Central tendency parameter
Dispersion parameter*
/ ( Mean , X ) .
*
1 290.4138.1
/ ( Median ) . . . n+1/2 . n/2 n/2 +1 .*
: 11 :
110112 115115 115 118 120 120122 124126
N= 11M= n+1/2 = 11+1 / 2 = 6 118 .
*
/ ( Mode ) . 110112 115115 115 118120120122124126
115 *
131 57 146*
Guassian distribution .
.*
66 65 65.7*
/ 110112 115115 115 118 120 120 122 124 126
16 126 110 .*
( Standard deviation ) .
*
Coefficient of variation /CV .
.
mean CV % = SD 100 /*
Bias% = expected observed/ expected *100
F .
F =
F .
*
F / 2 31 SDmg/dl2 . 21 SD mg/dl 1 . F 4 F . .
*
Correlation Coefficient( r ) x y +1 -1 . r r . r 0.95 .
r = *
F Paired t test .
*
Linear regression or Least square analysis .
X y . 45 .
*
Linear regression or Least square analysisy = ax + b
b =
a = y b x
*
.
S y/x = *
Quality Goal
Allowable bias
Total allowable Error
Allowable Imprecision
3sd 1262sd 1241sd 122Mean 120-1sd 118-2sd 116-3sd 114
3sd 144
2sd 136
1sd 128
Mean 120
-1sd 112
-2sd 104
-3sd 96
( 20 ) 5 4
2 . .
. . . .
.
90 5% (false rejection) .
Levey-Jenning
Levey- Jenning 2sd : 5%
3sd : 1%
Westgard mutirule 12s : Warning13S : Rejection22s : Rejection41s : Rejection10 mean : RejectionR4s : Rejection
2SDmean 2SD mean .
12s : Warning
13S : Rejection
22s : Rejection
R4s : Rejection
2006 . 1 2s 10 x 4 1s 2SD .
3 ( 3)
( )
/ ... ...
...
1- 2-
.
3- . : Ladenson 3 : 20% 50 % 5%50% labeling .
4- limit check
Intra Laboratory duplicate
Patient meanClinical decision correlation
Post analytic
Critical ValueGlucose 40 400 mg/dLPotassium 2.8 6.2 mmol/LSodium 120 160 mmol/LCalcium 6 13 mg/dL
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