Related Experiment Video
Updated: Jul 2, 2026

Study of In Vivo Glucose Metabolism in High-fat Diet-fed Mice Using Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT)
Published on: January 7, 2018
Reproducibility of the oral glucose tolerance test in overweight children
I M Libman1, E Barinas-Mitchell, A Bartucci
1Children's Hospital of Pittsburgh, and Department of Epidemiology, Graduate School of Public Health, Center for Exercise and Health-Fitness Research, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. ingrid.libman@chp.edu
Objective:
We examined the reproducibility of the oral glucose tolerance test (OGTT) in overweight children and evaluated distinguishing characteristics between those with concordant vs. discordant results.
Design:
Sixty overweight youth (8-17 yr old) completed two OGTTs (interval between tests 1-25 d). Insulin sensitivity was assessed by the surrogate measures of fasting glucose to insulin ratio, whole-body insulin sensitivity index, and homeostasis model assessment of insulin resistance, and insulin secretion by the insulinogenic index with calculation of the glucose disposition index (GDI).
Results:
Of the 10 subjects with impaired glucose tolerance (IGT) during the first OGTT only three (30%) had IGT during the second OGTT. The percent positive agreement between the first and second OGTT was low for both impaired fasting glucose and IGT (22.2 and 27.3%, respectively). Fasting blood glucose had higher reproducibility, compared with the 2-h glucose. Youth with discordant OGTTs, compared with those with concordant results, were more insulin resistant (glucose/insulin 2.7+/-1.4 vs. 4.1+/-1.8, P=0.006, whole-body insulin sensitivity index of 1.3+/-0.6 vs. 2.2+/-1.1, P=0.003, and homeostasis model assessment of insulin resistance 10.6+/-8.1 vs. 5.7+/-2.8, P=0.001), had a lower GDI (0.45+/-0.58 vs. 1.02+/-1.0, P=0.03), and had higher low-density lipoprotein cholesterol (117.7+/-36.6 vs. 89.9+/-20.1, P=0.0005) without differences in physical characteristics.
Conclusions:
Our results show poor reproducibility of the OGTT in obese youth, in particular for the 2-h plasma glucose. Obese youth who have discordant OGTT results are more insulin resistant with higher risk of developing type 2 diabetes mellitus, as evidenced by a lower GDI. The implications of this remain to be determined in clinical and research settings.
More Related Videos
08:30Intraperitoneal Glucose Tolerance Test, Measurement of Lung Function, and Fixation of the Lung to Study the Impact of Obesity and Impaired Metabolism on Pulmonary Outcomes
Published on: March 15, 2018
06:13Randomized Controlled Trial to Study the Acute Effects of Strength Exercise on Insulin Sensitivity in Obese Adults
Published on: December 1, 2023
Related Concept Videos
Hyperglycemia
Diabetes Mellitus: Type 2 and Gestational
Hypoglycemia and Glucagon
Glucose Transporters
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
Type II Diabetes Mellitus III: Clinical Manifestations and Diagnosis
Diabetes: Symptoms, Diagnosis, and Complications