REPRODUCIBILITY OF THE SHORT INSULIN TOLERANCE-TEST

The short insulin tolerance test is a simple method of estimating insu lin resistance by measuring the rate of fall of blood glucose followin g the intravenous administration of insulin. To determine its reproduc ibility, 18 healthy subjects underwent duplicate insulin tolerance tes ts separated by at least 1 week. Intravenous insulin (0.05 units kg-1) was administered into an antecubital vein and arterialized venous sam ples were obtained from a retrogradely cannulated vein on the dorsum o f the hand on the same side. The test was terminated with an intraveno us glucose injection 15 min after the administration of insulin. The m ean whole blood glucose concentration fell from 4.6 mmol l-1 to 2.8 mm ol l-1 while plasma insulin concentrations rose to supraphysiological leveLs and decLined exponentially. The glucose disappearance rate (K(i tt)) calculated from the slope of the fall in log transformed blood gl ucose between 3 and 15 min after insulin injection ranged from 2.1 to 6.5 (mean 4.4) % min-1 during the first visit and 1.7 to 7.4 (mean 4.4 ) % min-1 during the second. The ratio of the within-subject to betwee n-subject variance of the test was 0.24, the within-subject coefficien t of variation was 13 % and the between-subject coefficient of variati on 26 %. The short insulin tolerance test is reproducible and could be used to measure insulin resistance in large-scale epidemiological stu dies.