The glucose tolerance test (GTT) measures the body’s response to glucose (sugar). The body breaks down some of the foods your child eats into sugar. The blood carries the sugar to the cells of your child’s body. Your child needs some sugar in his cells for energy, but too much sugar in the blood is not good for your child’s health. This test will be done after your child has fasted, and again a few hours after he drinks a special sugar drink.
This test is also called an oral glucose tolerance test (OGTT).
The most common use of this test is to check for diabetes. Diabetes is a problem with the way the body makes or uses insulin. Insulin is made by the pancreas, which is an organ in the upper belly. The body uses insulin to help move sugar from the blood into the cells. When the body does not have enough insulin or has trouble using the insulin the body makes, sugar cannot get into the cells and builds up in the blood.
If your child is having a fasting glucose test, your healthcare provider will tell you when your child should stop eating and drinking before the test. In most cases your child should eat nothing and drink nothing but water for at least 8 hours before the test.
If your child is having a random or timed test, follow the instructions from your healthcare provider.
Your child may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that your child is taking. Ask your provider before stopping any of your child’s regular medicines.
Talk to your child's healthcare provider if you have any questions about the test.
Your healthcare provider may poke your child’s finger with a small needle (lancet) and fill a small tube with the blood. Or a small amount of blood may be taken from the arm with a needle.
Your child will then drink a liquid containing a certain amount of glucose. It tastes very sweet. Your child will have blood tests every 30 to 60 minutes for several hours after he has this drink.
Ask your healthcare provider when and how you will get the result of the test.
Blood glucose level may be higher than normal (hyperglycemia) if:
Test results are only one part of a larger picture that takes into account your child's medical history and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about the result and ask questions, such as: