The Oral Glucose Tolerance Test (OGTT) is a test to measure your body’s response to glucose, and can tell if you are at risk for or have diabetes. The glucose tolerance test is also used in a modified form to diagnose gestational diabetes, which can appear during pregnancy. For the OGTT, your blood glucose levels will be measured at the beginning of the test. You will then be asked to drink a solution with 75 grams (2.6 ounces) of glucose (sugar). After 2 hours, your blood glucose levels will be measured again, to see if your cells take up the glucose normally, or if it’s left in your bloodstream, indicating that there is a problem with your blood sugar. A normal blood glucose level after 2 hours will be lower than 140 mg/dL (7.8 mmol/L). If you have a blood glucose level between 140 and 199 mg/dL (7.8 and 11 mmol/L), it is considered impaired glucose tolerance, which is also called pre-diabetes, as you are at risk to develop diabetes. If you have blood glucose levels of 200 mg/dL (11.1 mmol/L), it can indicate that you have diabetes. Follow the directions of your doctor or healthcare provider before, during and after the test.
Sources:
- Mayo Clinic. Glucose tolerance test. https://www.mayoclinic.org/tests-procedures/glucose-tolerance-test/about/pac-20394296 (accessed 8. August 2020)
- AFP, Australian Family Physician. Oral glucose tolerance testing. https://www.racgp.org.au/afp/2012/june/oral-glucose-tolerance-testing/ (accessed 8. August 2020)
- WebMD. Do I Need an Oral Glucose Tolerance Test? https://www.webmd.com/diabetes/guide/oral-glucose-tolerance-test (accessed 8. August 2020)
