The glucose tolerance test is a lab test to check how your body moves sugar from the blood

into tissues like muscle and fat. The test is often used to diagnose diabetes.A blood sugar

level below 140 mg/dL (7.8 mmol/L ) is considered standard. A blood sugar level of 140

mg/dL (7.8 mmol/L ) to less than 190 mg/dL (10.6 mmol/L ) indicates the need for a three-

hour glucose tolerance test to diagnose gestational diabetes.