What is a Glucose Tolerance test?
The Glucose Tolerance Test (GTT), also referred to as the Oral Glucose Tolerance Test (OGTT), is a method which can help to diagnose instances of diabetes mellitus or insulin resistance. The test is a more substantial indicator of diabetes than finger prick testing.
It involves having a blood test in the morning, when you have not had any food or drink for 8 to 10 hours (though you can usually drink water, but check with the hospital if you’re unsure). You’re then given a glucose drink.
After resting for 2 hours, another blood sample is taken to see how your body is dealing with the glucose.
The OGTT is done when you’re between 24 and 28 weeks pregnant. If you’ve had gestational diabetes before, you’ll be offered an OGTT earlier in your pregnancy, soon after your booking appointment, then another OGTT at 24 to 28 weeks if the first test is normal.