Limiting level of hyperglycemia in diabetics.

Blood sugar levels were determined by the micromethod of Fujita and Iwa take.4) The limiting level of hyperglycemia was estimated from the results of one and two-dose glucose tolerance tests. In the one-dose test, 50g. of glucose was given orally following an overnight fast. Blood specimens were collected from the ear lobe before and every 30 minutes for 3 hours after the administra tion of glucose. The two-dose test was performed within 3 days after the onedose test. The procedure was the same, except that a second 50 g. dose of glucose was administered one hour after the first dose. Both the one-dose and twodose glucose tolerance tests gave a "one-peaked" curve. A "presumed" two-dose loading curve was constructed from the onedose curve by adding the difference between the fasting level and values at 1/2, 1, 1 1/2 and 2 hours, to the observed levels at 1 1/2, 2 1/2 and 3 hours, respectively. To obtain the limiting level of hyperglycemia, the actual two-dose loading curve is compared with the "presumed" two-dose curve. If the peak level in the actual test is less than the peak of the " presumed curve ", or does not exceed the presumed curve by more than 10 mg. %, the peak level in the actual two-dose test is taken as the " limiting level of hyperglycemia " (Table I). If the peak of the actual two-dose test exceeds the " presumed " peak level, it is likely that a three-dose or four-dose test would be needed to reveal the true " limiting level of hyperglycemia." Seven cases were encountered in whom the