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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