Oral Glucose Tolerance Test

What is an oral glucose tolerance test?

A glucose tolerance test shows how your child’s body handles sugar (glucose). The test shows if your child has high or low blood sugar after eating.

How to prepare for an oral glucose tolerance test

Always follow your care team's instructions for how to prepare for the test. The test lasts about 2 hours.

• Your child will need to follow fasting guidelines or NPO guidelines for when to stop eating and drinking. At the specified time before the test (generally 8 hours), stop giving your child solid food, enteral (tube) feeds, and liquids. They can continue to drink water.
• Give your child their usual medicine(s) the morning of the test unless the care team tells you not to do so.
• Have your child wear comfortable clothes.
• Bring activities such as books, games, or tablets that your child can do during the test.

What to expect during an oral glucose tolerance test

Your care team will explain what to expect during your child's test. In general, for this test:

• You can stay with your child during the test.
• Before the test, the care team will place an IV in your child’s arm.
• The care team will give your child a sweet liquid (glucose solution) to drink over 5 minutes.
• Before and every 30 minutes during the test, the care team will draw blood samples through the IV. They will draw blood samples for a total of 2 hours. The lab will measure the amount of glucose in your child’s blood samples.
• A nurse will check your child’s vital signs during the test.
• At the end of the test, the nurse will remove the IV.

Possible risks of an oral glucose tolerance test

Your child may have minor side effects from the sugary drink or the needle stick for the IV. After drinking the sugary drink, your child may feel nauseated for a short time. Any side effects should go away soon after the test. 

After an oral glucose tolerance test 

Your child can return to normal activities after the test.

Blood samples will be sent to a lab for testing. Your care team will let you know when to expect the test results and explain the results to you. 

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