IVGTT in Diagnosing of Glucose Kinetics Dis-balance in Diabetic Patients

Currently, there are two approaches that are used during the clinical diagnostics of diabetes: (a) according to the results of a static study of glycemia (in a fasting state and/or at a random point within 24 hours), and diabetes is diagnosed when the glycemia level exceeds a certain threshold value; (b) using a dynamic stress test, or OGTT (2 hours after taking 75g glucose), which also sets threshold values for normal glycemia at the 2-hour test point. But as early as 1943, another dynamic method for diagnosing diabetes, IVGTT (Greville), was proposed, in addition to OGTT. The advantages of the IVGTT method over the OGTT method in the accuracy of diagnosing diabetes are obvious. First of all, this is due to the fact that insulin has no influence on the absorption of glucose, but only on the rate of glucose elimination from blood. And, in the OGTT, not only the elimination of glucose from blood is reflected, but also the processes of glucose absorption from the gastrointestinal tract, which have nothing to do with insulin deficiency. On this basis, in 1943, Greville suggested using IVGTT for diagnosing diabetes and, as stated in this study, was quite successful. Moreover, to calculate the rate of glucose elimination from the blood, Greville proposed a simple kinetic model where the rate of glucose decreases in blood (dC(t)/dt) after an intravenous bolus injection (approximately 20g, IV push for a few minutes) was considered proportional to the concentration of blood glucose (C) with a proportionality factor of k:

dC(t)/dt= -k*C(t) (1)