In contrast to the end point method addition of mutarotase to the reagents is not necessary. Evaluation of absorbance recordings is done in the usual way, calculation of glucose concentrations via a glucose standard, which is treated and analyzed together with the samples. The following results have been obtained with this method: Using the LKB 8600 Reaction Rate Analyzer and the Eppendorf 5010/20 Enzyme Analyzer the correlation between AA/t and glucose concentrations is linear up to 16.7 mmol/t (300 mg/100 ml). Higher glucose concentrations are found low, the error at 27.8 mmol/1 (500 mg/100 ml) glucose is -10~o. Accuracy of the method was tested with NBS standard reference glucose (5 fold determinations) : In the range between 1.7 and 16.7 mmol/l (30-300 mg/100 ml) glucose recovery is 9 8 1 0 2 ~ with a srd = + 2 ~ . Analysis of several control sera with declared glucose concentrations between 4.3 and 17.1 mmol/1 (77 to 307 mg/100 ml) yielded recoveries of 95-105 ~o. Comparative glucose determinations have been performed on human sera (glucose concentrations between 3.3 and 16.7 mmol/1 (60-300 mg/100 ml)] using the following methods: I. Hexokinase with deproteinization of sample (x) vs. kinetic glucose dehydrogenase method without deproteinization of sample (y), 2. Hexokinase method with deproteinization of sample (x) vs. kinetic glucose dehydrogenase method with deproteinization of sample (y), 3. Kinetic glucose dehydrogenase method with deproteinization of sample (x), vs. kinetic glucose dehydrogenase method without deproteinization of sample (y). The results of these measurements are (glucose concentrations in mmol/l) :