Oral Glucose Tolerance Test
What is an oral glucose tolerance test?
Why would a doctor recommend an oral glucose tolerance test?
What does an oral glucose tolerance test involve?
How long is the recovery after an oral glucose tolerance test?
An oral glucose tolerance test helps a doctor diagnose diabetes. It is often used to check for gestational diabetes, a condition that some women develop during the late stages of pregnancy. The test measures a person's ability to process glucose, the sugar that is used by the body as fuel. After the patient drinks a glucose solution, the doctor checks the patient's blood sugar levels several times over a period of hours.
A shorter glucose challenge screening test evaluates pregnant women for gestational diabetes. This is usually done between the 24th and 28th week of pregnancy. If the results of the screening test show that a woman might have gestational diabetes, a doctor will recommend the longer oral glucose tolerance test.
You must not eat or drink anything but water for about ten hours before the test. At the clinic or hospital, a nurse or technician will insert a needle into a vein in one of your arms, to collect a sample of your blood. You may feel a slight sting or moderate pain when the needle is inserted.
You will then drink a sweet glucose solution, about 2.5 to 3.5 ounces. The nurse or technician will draw several additional blood samples from your vein, usually three more times, on the hour, for the duration of the test.
These blood samples are then tested for glucose levels, to see how your body processes sugar. In the blood of a person without diabetes, glucose levels will rise initially, then return quickly to normal. In a person with diabetes, the blood glucose levels will take much longer to return to normal.
You may return home after the test and resume your normal activities. Some people may feel throbbing in their arm after the test, or feel slightly dizzy or faint.
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