Table 2.

The preanalytical uncertainty budget shows the expected bias, variance, and SD of the differences between current practice and the standard method for each uncertainty source and the sum of the expected biases and variances.

Uncertainty sourcesGlucose, mmol/LCalcium, mmol/LMagnesium, mmol/LCreatinine, μmol/L
BiasVarianceSDBiasVarianceSDBiasVarianceSDBiasVarianceSD
Different blood tubes−0.0030.0010.032−0.00040.000030.00550.0010.000320.0179−0.21.171.08
Clotting time−0.0910.0050.071−0.0100.000070.0084<0.0010.000020.0045−0.020.0040.06
Centrifugal force−0.0080.0010.032−0.0020.000040.00630.0010.000030.0055−0.20.430.66
Storage time−0.0580.0060.0770.0020.000080.00890.0030.000090.00951.11.661.29
Different instruments0.0090.0050.071−0.0010.000110.01050.0010.000200.0141−0.20.020.14
Combined biases and variances−0.150.0170.130−0.0110.000330.01820.0060.000660.02570.53.281.81