Encyclopedia of Behavioral Medicine

2013 Edition
| Editors: Marc D. Gellman, J. Rick Turner

Oral Glucose Tolerance Test (OGTT)

Reference work entry
DOI: https://doi.org/10.1007/978-1-4419-1005-9_769



The OGTT test is used for the diagnosis of prediabetes, diabetes, and rare disorders of carbohydrate metabolism. The OGTT is a procedure in which a standardized load of glucose is provided and plasma glucose levels are drawn at different times over a 2-h period. Insulin levels could be also obtained to determine insulin resistance. Normal values for fasting glucose levels are below 100 mg/dL. Impaired fasting plasma glucose levels are considered between 100 and 125 mg/dL, and fasting plasma glucose levels above 126 mg/dL are considered in the diabetes range. The 2-h glucose level will help in the definitive diagnosis of diabetes. Plasma glucose levels above 200 mg/mL are diagnostic for diabetes mellitus. Levels between 140 and 200 mg/mL at 2 h are considered in the prediabetes range.


A diet that includes at least 60% of calories as carbohydrates should be provided at least for 3 days before the test. The test should not be performed if there...

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References and Readings

  1. Lifshitz, F. (2007). Pediatric endocrinology (5th ed., p. 755). New York: Informa Healthcare.Google Scholar

Copyright information

© Springer Science+Business Media, New York 2013

Authors and Affiliations

  1. 1.Department of PediatricsMiller School of Medicine, University of MiamiMiamiUSA