Evaluation of a glucose oxidase-peroxidase method adapted to the single-channel autoanalyzer and SMA 12-60.

The glucose oxidase-peroxidase method for determining serum glucose, with the ammonium salt of 2,2’-azine-di (3 ethyl benzothiazoline-(6)-sulfonic acid) as the chromogen, was adapted to use with the single-channel AutoAnalyzer and the SMA 12/60 (Technicon Corp.). The extended linearity (up to 500 mg/100 ml on both systems) eliminated the need for numerous dilutions in the 300 to 500 mg/100 ml range as required by other methods of analysis. Recovery of added glucose was excellent. Supranormal concentrations of uric acid and ascorbic acid interfered with recovery, but the effects of elevated bilirubin, creatinine, and urea, and of gross hemolysis were negligible. Sera of 337 patients (glucose concentrations: 50 to 454 mg/100 ml) were analyzed by this method on both instruments and by an automated o-toluidine method. By the latter procedure, the glucose concentration averaged 10 mg/100 ml higher. Sera from uremic patients, measured by the o-toluidine method, had glucose values up to 28.0 mg/100 ml higher than the values obtained by the glucose oxidase method. The glucose oxidase method of measuring serum glucose is a more accurate and precise index of “true glucose” than either the o-toluidine or the neocuproine methods.