Your doctor may order an OGTT if she suspects you are developing diabetes. You will be told not to eat or drink after midnight the night before the OGTT. At the time of testing, your blood will be taken, and then you will drink a liquid containing glucose. Your blood is taken again, and your blood glucose level is tested every 30 to 60 minutes (for up to two to three hours) to assess how the glucose is metabolized.
A blood glucose level of 200 mg/dl or greater is indicative of diabetes.


