Glucose Tolerance Test

Excerpt

A glucose tolerance test (GTT) is a procedure that determines whether a patient can use and store glucose normally. The test is typically used to diagnose diabetes mellitus, insulin resistance, impaired pancreatic β-cell function, and, occasionally, reactive hypoglycemia or acromegaly, as well as rarer disorders of carbohydrate metabolism. In the most commonly performed version, the oral glucose tolerance test (OGTT), a standard dose of glucose is ingested by mouth, and blood levels are measured 2 hours later. Many variations of the GTT have been developed over the years for different purposes, with varying standard glucose doses, administration routes, sampling intervals, and measurements of additional substances beyond blood glucose.