Comparison of plasma, serum, and whole blood ethanol concentrations.

The differences in ethanol concentrations, as measured by direct injection gas chromatography, among plasma, serum, and whole blood from living human subjects are examined. The samples containing serum and the corresponding ones containing whole blood arrived at the laboratory as part of the same submission. The ratio of the concentration of ethanol in serum to that in plasma is 1.00 +/- 0.01:1 with a range of 0.98:1 to 1.04:1. The serum/whole blood ratio and plasma/whole blood ratio are both 1.12 +/- 0.02:1. The former has a range of 1.09:1 to 1.18:1 and the latter ranges from 1.09:1 to 1.17:1.