Evaluation of the hexokinase/glucose-6-phosphate dehydrogenase method of determination of glucose in urine

The two-step enzymic method for determination of glucose, using hexokinase for phosphorylation of the glucose and glucose-6-phosphate dehydrogenase for the subsequent reduction of triphosphopyridine nucleotide to its reduced form measurable at 340 nm, was evaluated for its suitability for urine analysis. The glucose oxidase method, previously considered the best available, is subject to serious interference which cannot be removed without destroying the accuracy of the method. The hexokinase/G6PD method is highly specific and interference-free. The only possible urinary interference that could be found is a diminution of the glucose indication in the presence of extremely abnormal fructose concentrations. The method was tested for recovery on 100 clinical urine samples. A normal range of 0 to 20 mg100 ml role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{20 mg}\text{100 ml}$$\text{20 mg}\text{100 ml}$ glucose was indicated by these samples. The method may also be used for blood analysis as normal concentrations of preservative did not interfere. The general analytical and kinetic characteristics of the method were examined, showing that the method may be used accurately at ambient temperatures, with a straight line standard curve, at an incubation time of 10 min, for sample concentrations up to 100 mg100 ml role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{100 mg}\text{100 ml}$$\text{100 mg}\text{100 ml}$. The method may be used for screening purposes without determining the background ultraviolet absorbance of the sample.