Glucose Tolerance Test (GTT)

An appointment is required for this test. Please phone your nearest TML Pathology collection centre to make arrangements.

On the night before the test

• Please do not eat, chew gum or drink any fluids (except water) for at least 8 hours before the test. It is preferable you do not fast for more than 12 hours.
• Water with no additives can be consumed.
• Record your height and weight.
• Record any recent and current medication.

On the morning of the test

• Bring your medication list and height/weight details.
• Do not physically exert yourself prior to or during the test (including brisk walking to the clinic).
• Avoid smoking for an hour prior to and during the test. If this is not possible, please inform staff.
• Illness can affect glucose tolerance, if you are ill within 3-4 days of the test, contact your doctor to ask whether they want you to postpone the test.
• You will be required to drink a glucose solution within a 5 minute timeframe. This solution contains the following food additives:
  • 330-ascorbic acid
  • 211-sodium benzoate
  • 202-potassium sorbate
  • Sulphites

Do not proceed with the test if you have a known allergy to any of these additives. Contact your doctor and advise your allergy is preventing you from proceeding with the GTT drink.

The test usually takes approximately 2 hours (unless your doctor specifies otherwise).

This is a special test which is only performed at selected TML Pathology collection centres. To find a centre which performs this test select “Glucose Tolerance Test (GTT)” from the “Any test” drop down in our Collection Centre search, or alternatively call (03) 6711 2000 (Launceston area) or (03) 6108 9900 (Hobart area).