What is the glucose tolerance test (GTT) and what are normal values?
An oral glucose tolerance test is done to check the body’s ability to process sugar. The test begins with blood being drawn in the morning after fasting overnight (usually more than 8 hours, but less than 16). The patient then drinks a bottle of “glucola” a special drink prepared with 75 grams of glucose (sugar). There is some variation in how many blood draws are made. Some will only check the 2-hour level, though most commonly blood draws are made at 1 hour, 2 hours, and 3 hours. Some labs will also draw at 30 minutes, and/or at 4 hours. Normal values are: Glucose Tolerance Test Glucose and Insulin Values Time Normal Glucose Values Normal Insulin Values What the Results Mean Fasting < 126 mg/dl < 10 mIU/ml Normal glucose results are 70-90, 111 or over is impaired, 126 or over is diabetic. Insulin levels above 10 show insulin resistance. hour < 200 mg/dl 40-70 mIU/ml A truly normal glucose response will not exceed 150. 1 hour < 200 mg/dl 50-90 mIU/ml Some want to lower the threshold o
An oral glucose tolerance test is done to check the body’s ability to process sugar. The test begins with blood being drawn in the morning after fasting overnight (usually more than 8 hours, but less than 16). The patient then drinks a bottle of “glucola” — a special drink prepared with 75 grams of glucose (sugar). There is some variation in how many blood draws are made. Some will only check the 2-hour level, though most commonly blood draws are made at 1 hour, 2 hours, and 3 hours. Some labs will also draw at 30 minutes, and/or at 4 hours. Normal values are: Glucose Tolerance Test — Glucose and Insulin Values TimeNormal Glucose ValuesNormal Insulin ValuesWhat the Results MeanFasting< 126 mg/dl< 10 mIU/mlNormal glucose results are 70-90, 111 or over is impaired, 126 or over is diabetic. Insulin levels above 10 show insulin resistance.½ hour < 200 mg/dl 40-70 mIU/mlA truly normal glucose response will not exceed 150. 1 hour< 200 mg/dl 50-90 mIU/mlSome want to lower the threshold on glu
