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