Difference in Glucose Levels between Capillary and Venous Whole Blood During 75g OGTT in Healthy Subjects

Abstract

We studied the difference in glucose levels between capillary (C) and venous (V) whole blood during 75g oral glucose tolerance test (OGTT) in healthy subjects.
The post-loaded glucose levels in capillary blood were significantly higher than those in venous.blood (p<0.01), and the mean values of C-V difference at 30, 60, 90, 120 and 180 min were 24.6, 25.2, 19.3, 17.1 and 9.3, respectively, with the maximum difference at 60 min.
No correlation was found between the magnitude of C-V difference and the levels of glucose in 75 healthy volunteers, although varying C-V differences (-9-52 mg/dl) were observed among them.
Out of 75 subjects 16 had different diagnosis depending on the measurement of either C or V glucose values. Moreover, many subjects, 24 out of 75, were diagnosed to be impaired glucose tolerance (IGT) when evaluated by C blood glucose. These findings indicate that the criteria, recommended by Japan Diabetes Sociaty, for judging C blood glucose levels may be low when compared with those for V glucose.