Effect of Addition of WZB117 as an Inhibitor of Glucose Transporter 1 for Venous Blood Glucose Determination.

Abstract

Sodium fluoride (NaF) has been applied to inhibit glycolysis in venous specimens for decades. However, it has had little effect on the rate of glycolysis in the first 1 to 2 hours, resulting in a decrease of glucose, so a more efficient method is needed. Recently, we discovered that WZB117, a specific Glut1 inhibitor, restricts glycolysis by inhibiting the passive sugar transport of human red blood cells and cancer cells. The purpose of this study was to evaluate the results of intravenous blood glucose determination after the addition of WZB117. Venous specimens from 40 pairs of healthy volunteers were collected for several days and placed in tubes containing NaF plus EDTA-disodium (Na2) without WZB117 (the A group); citric acid, trisodium citrate, and EDTA-Na2 without WZB117 (B group); and NaF plus EDTA-Na2 with WZB117 (C group). The glucose concentration was measured after venipuncture and compared with test tubes treated for 1 hour, 2 hours, and 3 hours before centrifugation. Glucose level was determined by the hexokinase method. The paired t-test was used to examine differences in glucose values at baseline and at different time points. The number of misdiagnoses and the misdiagnosis rate were calculated at 2 diagnostic stages: high risk of diabetes (glucose level of 6.1 mmol/L) and diagnosis of diabetes (glucose level of 7.0 mmol/L). Glucose levels decreased by 1.0% at 1 hour and by 2.1% at 3 hours in the C group tubes and simultaneously decreased by 1.7% at 1 hour and by 2.5% at 3 hours in the B group tubes. In contrast, glucose levels decreased by 4.1% at 1 hour and by 6.3% at 3 hours in the A group tubes. There was a statistically significant difference in glucose levels measured in the A group tubes and B group tubes at 1 hour, 2 hours, and 3 hours. The misdiagnosis rate of clinical diagnosis in diabetes was highest in the A group tubes (7.0‰ at 1 hour, 0.1‰ at 3 hours at 7.0 mmol/L point; 14.6‰ at 1 hour, 0.4‰ at 3 hours at 6.1 mmol/L point) and lowest in the C group tubes (2.95‰ at 1 hour, 0‰ at 3 hours at 7.0 mmol/L point; 4.8‰ at 1 hour, 0.1‰ at 3 hours at 6.1 mmol/L point). The tube addition of WZB117 is more suitable for minimizing glycolysis and has no effect on glucose levels even if specimens are left uncentrifuged for up to 3 hours.