Test Overview

• Test Overview
• Why It Is Done
• How To Prepare
• How It Is Done
• How It Feels
• Risks
• Test Results
• What Affects the Test
• What To Think About

The oral glucose tolerance test (OGTT) measures the body's ability to use glucose. Glucose, a type of sugar, is the body's main source of energy. A hormone called insulin helps the body use and control the amount of glucose in the blood. People with Diabetes do not produce insulin or cannot use insulin effectively. An OGTT is most commonly done to detect Diabetes that occurs with pregnancy (gestational diabetes).

For an OGTT, you drink concentrated glucose. Your glucose levels are then measured in one or more blood samples taken from a vein. Normally, blood glucose levels peak within an hour and then begin to drop.