Glucose Tolerance Tests

Glucose is a type of sugar that the body uses for energy. An oral glucose tolerance test (OGTT) is a test that analyzes our body’s ability to turn the sugar into energy and can be used to diagnose diabetes.

1 Hour Test

You will receive drink and lab orders at your routine OB visit.

1. This test is mean to be a random test. You DO NOT need to fast for this test.
2. Drink the entire 10 oz bottle of glucose solution within 10 minutes of opening it. Write down the time that you finish the drink.
3. You must have your blood drawn EXACTLY one hour after finishing the glucose solution. Please arrive at the laboratory AT LEAST 20-30 minutes prior to when you need your blood drawn. This will allow the Laboratory time to complete your paperwork which must be done before they can draw your blood.
4. If you have an RH negative blood type you MUST receive your antenatal RhoGAM within 72 hours of having your blood drawn. Your test results will not be complete for a minimum of 1 hour and 30 minutes. Before leaving the laboratory, please make an appointment with the OB Department or Same Day Surgery to receive your RhoGAM injection.

3 Hour Test

You may need to have the 3 hour glucose test if your 1 hour test was abnormally high or if your doctor would like additional testing.

Remember to tell your doctor about all prescription and nonprescription medications you are taking, as your doctor may advice that you stop taking some before the test.

1. You will need to schedule this test at the facility of your choice.
2. You should follow an unrestricted diet, consuming at least 150 grams of carbohydrates per day for at least 3 days, prior to the test.
3. DO NOT eat after 9pm the night before the test. You MUST be fasting for at least 12 hours prior to the test.
4. Upon arrival at the hospital, your blood will be checked for a fasting glucose level. Then you will be asked to quickly drink a liquid containing glucose. Your blood will be drawn at 1, 2, and 3 hours.
5. This test may take up to 4 hours. You will be asked to sit quietly during the test to avoid any kind of activity interfering with the results.
6. Do not eat during the test. You may only drink water.