<prompt> A pregnant female presented with a family history of diabetes. Her glucose tolerance test GTT is positive. All of the following are TRUE about GTT, EXCEPT:It is useful in reactive hypoglycemiaFasting of 8-12 hours is requiredMost impoant sample is at 2 hoursPatient is instructed to drink glucose within 10 minutes  <response>: Glucose tolerance test GTT: After an 8-12 h overnight fast, a fasting blood glucose sample is drawn, and the patient ingests a 75-g oral glucose load 100 g for gestational DM screening, 1.75 mgkg ideal body weight in children up to 75 g. The glucose load is consumed within 5 minutes. Blood is drawn at 30 min, 1, 2 and 3 h after glucose load. An oral glucose tolerance test is normal if the fasting venous plasma glucose value is less than 100 mgdL 5.6 mmolL and the 2-hour value falls below 140 mgdL 7.8 mmolL. A fasting plasma glucose value of 126 mgdL 7 mmolL or higher or a 2-hour value of greater than 200 mgdL 11.1 mmolL is diagnostic of diabetes mellitus. Reactive hypoglycemia can be evaluated using the oral GTT. Ref: German M.S. 2011. Chapter 17. Pancreatic Hormones and Diabetes Mellitus. In D.G. Gardner, D. Shoback Eds, Greenspans Basic Clinical Endocrinology, 9e. 