‘Spontaneous’ Variability of Oral Glucose Tolerance

Abstract

During the course of an investigation of the carbohydrate metabolism of non-diabetic subjects we have been struck by the frequent occurrence of wide variations in the blood-sugar levels of individuals on repetition of the oral glucose tolerance test. Since this procedure is widely utilized under the impression of its consistency of results, it has seemed desirable to present our experience with it. Despite the multiplicity of investigations in this field, there is a surprising dearth of information concerning the stability of this reaction in the individual subject and under comparable conditions. In a study of two normal subjects with blood samples taken every few minutes, Bock, Schneider and Gilbert (1) found that on duplicate determinations there was a difference of 25 mg. per cent in one and 62 mg. per cent in the other at coincident points on the glucose tolerance curve. Glassberg's (2) series on 5 patients showed an average variation between two readings extending from 13 mg.