The glucose tolerance test measures the body's ability to metabolize glucose: Patients with untreated diabetes have high blood glucose levels. Glucose tolerance tests are one of the tools used to make the diagnosis of diabetes.
Why it is Recommended
The oral glucose
tolerance test is used to screen pregnant women for gestational diabetes
at between 24 and 28 weeks of pregnancy. It may also be used to diagnose diabetes
in cases where the disease is suspected despite a normal fasting blood glucose.
The most common glucose
tolerance test is the oral glucose tolerance test (OGTT). For adults, the test requires that the patient fast overnight, and then consume 100gm of glucose in water. Blood sugar measurements are then made at 1/2, 1, 2, 3, 4, 5 and 6 hour intervals after ingestion of the glucose load. Insulin
levels may also be measured.
For infants and children the preparation depends on various factors such as the child's age.