What is a Glucose Tolerance Test (GTT)?
To diagnose diabetes, a standardized amount (300 calories) of simple sugar is given to the patient in the form of an orange or cola flavored drink. The results of the blood sugars before and after the sugar challenge have been standardized through research studies to predict the development of diabetes and subsequent complications of the diabetes. At two hours after the sugar challenge, a blood sugar between 140 and 199 indicates impaired glucose tolerance. A blood sugar of 200 at two hours diagnoses diabetes. The other reason for doing the test is to determine if your body has to make an excessive amount of insulin to keep your blood sugar normal. If you have a normal blood sugar but are insulin resistant, you have an increased risk of developing diabetes, obesity, and heart disease. How to Prepare for the Test Make sure you are eating a normal diet for 2 days prior to the test. You should not be fasting or on only liquids for the two days prior to the GTT. You should not be on a diet
