AimTo assess a new formula to improve the screening of isolated impaired glucose tolerance (IGT) in youth with overweight/obesity (OW/OB). Methods and resultsA cross-sectional study was performed in 1189 Caucasian youths with OW/OB aged 5–17 years, in whom impaired fasting glucose and high glycosylated hemoglobin were excluded. The sample was divided into training set (TS) (n = 883) and validation set (VS) (n = 306). Fasting (FG) and post-load plasma glucose, alanine aminotransferase (ALT), lipids and familial history for type 2 diabetes (FD) were available in all individuals. In the TS youths with IGT (n = 58, 7.0%) showed higher prevalence of female sex (FS), FD, and higher levels of FG, post-load glucose, ALT and lower levels of HDL-cholesterol vs individuals without IGT. The linear formula was obtained by logistic regression analysis in the TS: 0.05∗ALT + 0.07∗FG + 0.87∗FD + (0.06∗HDL∗ − 1) + 1∗FS. The best cut-off was 5.84. The performance of the formula vs IGT was: sensitivity: 0.74 and specificity: 0.71. Similar results were obtained in the VS. ConclusionsUsing metabolic and anamnestic data we obtained a simple formula with a good performance for screening isolated IGT. This formula may support pediatricians to identify youths with OW/OB in whom the OGTT may be useful for detecting IGT.