Inaccuracy = Bias = (Laboratory Value - True Value)

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

True Value may be “EQAS Mean of Comparison”.

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

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

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

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

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

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