Glucose determination by automatic chemical analysis.

1HE GENERAL CONSTRUCTION and operation of an automatic chemical analyzer essentially identical with the one used in this study* has been described (1). Glucose is conveniently measured with this analyzer using the principle of the Hoffman method (2, 3). When using this method for the determination of blood glucose by automatic analysis, a change with time of the transmittance reading of a given standard is noted. This change is of sufficient magnitude that 3 or more standard curves are required over a period of 2 hours to avoid significant error in determining unknown concentrations. The variation in standard curves is caused, for the most part, by variations in dialyzer temperature. The use of a water bath for temperature control of the dialyzer greatly reduces this change. A water bath similar to the one constructed at this institution but with better temperature regulation is now available as standard equipment on the Technicon AutoAnalyzer and has been used for some of the experiments reported in this paper. Additional data are presented concerning the accuracy and precision of the automatic analyzer compared to a standard manual method for the determination of “true” blood glucose.