Oral Glucose Tolerance Test You are here:HomeFor patientsTest Instructions & Information PDF version PREPARATION: Three days of normal carbohydrate diet. Overnight fast, nothing to eat or drink (except water) for 10 hours prior to test (no longer than 14 hours as test results may be affected) No current illness (e.g. infection) or stresses (e.g. recent surgery or trauma) that might invalidate the test. Please inform pathology collector of any medications you are taking. DURING TEST: If at any time during the test you feel unwell please inform the pathology collector immediately. We suggest you bring a book or other material to help pass the time The test requires approximately 2 ½ hours and it is requested you commence the test prior to 10:30 am as glucose tolerance decreases in the afternoon. You are required to sit quietly for 30 mins prior to and during the test and must remain in the collection centre for the duration of the test. You must not smoke, eat or drink during the test. A blood sample will be collected prior to you drinking a measured dose of glucose. You will be requested to drink the measured dose of glucose in 10 minutes or less. Please inform the pathology collector if you have any problem doing so. At 1 hour after completing the drink, you will have a second blood sample collected. At 2 hours after completing the drink you will have a third blood sample collected to complete the test.