The intravenous insulin tolerance test is an accurate method for screeninga general population for insulin resistance and related abnormalities

To verify whether the short intravenous insulin tolerance test (ITT) (a saf e, reproducible, inexpensive, rapid and easy to perform measurement of insu lin sensitivity) is a suitable test for insulin resistance screening in a g eneral population, we measured in 60 non diabetic subjects, either non-obes e (no.=40) or obese (BMI>28, no.=20) the K of glucose disappearance from pl asma after ITT (K-ITT), plasma glucose (PG) and insulin (IRI) both fasting (FPG, FIRI) and at 120 min of OGTT (PG- 120, IRI- 120), and also triglyceri des (Tg), cholesterol (Chol) and blood pressure (BP). Subjects were subdivi ded into quartiles according to K-ITT values. Average FPG, PG-120, FIRI, IR I-120, Tg and Chol values were progressively increased, and average HDL/Cho l was progressively decreased from quartile 1 (the most insulin sensitive) to 4 (the most insulin resistant) (p<0.05, by 1-way ANOVA test). Also BP wa s increased in the insulin resistant patients, but statistical significance was not reached. Three or more of the studied parameters (FPG and/or PG-12 0, FIRI and/or IRI-120, Tg, HDL/Chol, mean BP) were altered (below the wors t 25 degrees percentile) in 64% of subjects from quartile 4; none of the su bjects in quartile 1 was affected by such a cluster of alterations. K-ITT v alues less than or equal to 4.8 identified the cluster of insulin resistanc e related alterations with an accuracy of 82% (sensitivity=83.3%, specifici ty=80.5%). In healthy subjects with a wide range of BMI the ITT is a reliab le procedure for screening for the cluster of metabolic alterations related to insulin resistance. (C) 1999, Editrice Kurtis.