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Validation of the low dose short insulin tolerance test for evaluation of insulin sensitivity
Author(s) -
Gelding S. V.,
Robinson S.,
Lowe S.,
Niththyananthan R.,
Johnston D. G.
Publication year - 1994
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1994.tb03012.x
Subject(s) - medicine , endocrinology , insulin sensitivity , insulin , insulin tolerance test , glucose tolerance test , insulin resistance
OBJECTIVES The assessment of insulin sensitivity requires an accurate and reproducible technique. The short insulin tolerance test is a simple and rapid method for screening large numbers of subjects when the fasting glucose level is normal. Conventionally, an insulin dose of 0·1 units/kg is used, but this may result in symptomatic hypoglycaemia in healthy thin subjects who are insulin sensitive. In order to overcome this problem we have employed a lower dose of insulin and have studied the reproducibility of this modified technique comparing it with the euglycaemic hyperinsulinaemic clamp. DESIGN Subjects were studied on two separate occasions, once by a short insulin tolerance test and on a second occasion by either a euglycaemic hyperinsulinaemic clamp (insulin infusion of 40 mU/m 2 /min) or a repeat short insulin tolerance test. PATIENTS Eleven healthy subjects were studied twice with a short insulin tolerance test. A further 10 healthy subjects received a short insulin tolerance test on one day and a euglycaemic hyperinsulinaemic clamp study on another occasion. MEASUREMENTS Insulin sensitivity was measured in the short insulin tolerance test using the slope of arterialized blood glucose concentration from 3 to 15 minutes after an intravenous bolus of short‐acting insulin, 0·05 units/kg body weight. In the clamp study, insulin sensitivity was derived from the average amount of glucose infused at steady state ( M ) and the mean plasma insulin level ( l ). RESULTS In the short insulin tolerance test no subject developed symptomatic or biochemical hypoglycaemia, defined as a blood glucose < 2·2 mmol/l. The (mean ± SEM) insulin sensitivities for the 11 subjects studied twice were 174±10 and 179±11 μmol/l/min with a coefficient of variation of 6·9±2·6%. There was a close correlation between insulin sensitivity derived from the short insulin tolerance test and that obtained from the euglycaemic clamp studies (so‐called M/l ratio) in the same subjects ( r = 0·81; P < 0·005). CONCLUSION The short insulin tolerance test employing 0·05 units/kg insulin is a safe, valid and reproducible method for the assessment of insulin sensitivity.