What is an oral glucose challenge test?

The oral glucose challenge test is performed to screen for gestational diabetes. This test involves quickly (within five minutes) drinking a sweetened liquid (called Glucola), which contains 50 grams of glucose. A blood sample is taken from a vein in your arm about 60 minutes after drinking the solution. The blood test measures how the glucose solution was processed by the body.

Normal blood glucose levels peak within 30 to 60 minutes after drinking the glucose solution. A higher than normal blood glucose level does not always mean you have gestational diabetes.

When is the oral glucose challenge test performed?

Gestational diabetes is generally diagnosed between the 24th and 28th week of pregnancy. If you have had gestational diabetes in a previous pregnancy, or if your health care provider is concerned about your risk of developing gestational diabetes, the test might be performed earlier.

On the day of the test, please follow instructions given to you by your health care provider or the lab (if applicable).

General guidelines: You may eat a light breakfast on the day of the test, avoiding items with high sugar content, such as orange juice, pancakes, and doughnuts. Report to your specified location for the Glucola drink. After drinking Glucola, do not ingest any food or drink and do not smoke until your blood is drawn, one hour later. This can be done at the time of one of your prenatal visits.

Further diagnostic test

If your health care provider determines your blood glucose level was elevated, you will have an additional gestational diabetes screening test. If this test is indicated, your health care provider will provide you with information.


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 3/10/2016...#9696