====Common Statistic of The Clinical Biochemistry====

**Inaccuracy = Bias =** (Laboratory Value - True Value) 

**Inaccuracy % = Bias % =** [(Laboratory Value - True Value) x 100] / True Value 

True Value may be "EQAS Mean of Comparison". 

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**Imprecision = CV% =** (IQC-SD x 100 / IQC-Mean) 

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**Total Error % (TE % ) =** (Bias % + 2CV%)

**Total Error (TE) =** (Bias + 2SD)

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**Standard Deviation Index = SDI =** (IQC Value - IQC Mean) /IQC-SD

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**Z Score =** (EQAS Value - EQAC Mean of Comparison) /EQAS-SDPA

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** Factor of The Analyte =** Concentration of Calibrator / (O.D. of Calibrator - O.D. of Blank )

**Concentration of Substrate / Analyte =** (O.D. of Substrate - O.D. of Blank ) x Concentration of Calibrator / (O.D. of Calibrator - O.D. of Blank ) 

**Concentration of Substrate / Analyte =** (O.D. of Substrate - O.D. of Blank ) x Factor

**Delta OD =** (OD at 60 second) - (OD at 0 Second) = Difference of OD in 60 Second (1 minute) interval

Note : In case of kinetic or End-Point kinetic method, Delta OD will be used instead of OD