Solids as a consideration in legal measurements: Blood ethanol concentration as a model

Abstract

One can easily conclude, based on the data derived with current equations for correcting for severe hypertriglyceridemia ( Steffes, M. W.; Freier, E. F., J. Lab. Clin. Med., 1976, 88, 683–688 ) or by determining the percentage of water in normalized plasma (serum) or whole blood, that assigning some absolute value for ethanol concentration may be based on questionable assay characteristics. Because the legal aspects of ethanol measurement are different from the medical aspects of analyte measurement, and because the purposes for which they are determined are different, we should use caution in interpreting the value as we measure it in one kind of sample (serum) in weight per unit volume for use in a legal case in which another kind of sample (whole blood) is specified perhaps as a percentage by weight (Michigan Drunk Driving Law, Public Act, 1982, 310). In addition, extrapolating from blood alcohol concentration to whole body alcohol concentration has already been shown to be specious or at least fraught with uncertainty (Hume, D. N.; Fitzgerald, E. F., Anal. Chem., 1985, 57, 876A–886A). Ethanol is found only in the water of blood. However, water alone and the percentage of associated solids dissolved or dispersed in the water are quite variable for legal measurements. Some more general way of including this variability should be designed specifically into any law which could have such dire consequences for a citizen. Obviously, no one should drive while even at an impaired level. However, drinking seems inevitable in our society and though it may cause disastrous effects, no members of society should be made victims of technicalities inherent in a poorly written law.