Dean Cruikshank

Testing for Diabetes


As most people know, the oral glucose tolerance test (OGTT) is a regular part of your yearly tests. To have an OGTT you must be fasting. This means nothing to eat or drink other than water for 12 hours before the test. The test takes 2 hours. Your blood sugar is measured and then you are asked to drink a sugar-drink. Your blood sugar is then tested again 2 hours after the drink. Two hours is the normal amount of time the body should take to absorb the sugar into your cells from your bloodstream. In a healthy body, insulin is released from the pancreas which triggers the absorption of sugar out of the blood and into the cells.

A high level of sugar in the blood tells us that the cells in the body have not absorbed enough of the sugar and there is impaired glucose tolerance, or diabetes. It is best to have the test done at a time when you are not sick, since illness can affect your body’s ability to efficiently use insulin. If you are booked for an OGTT and are unwell, please call the clinic ahead of time so the test can be re-scheduled. Also, if you have symptoms of diabetes, are pregnant, or are on oral steroids (prednisone) we may do the test more often because these situations place you at higher risk for developing diabetes.