Glucose tolerance test

Glucose tolerance test

An appointment is needed for this test, so please phone the laboratory on (04) 381 5900 to book, and for any further information.

About your Test 

  • Your health professional has requested this test to help in the diagnosis of diabetes.
  • You will need to telephone the laboratory to make an appointment.
  • You need to fast for at least 8 hours and no more than 14 hours before the test.
  • You should enjoy your normal diet without restrictions, including sugar.  Take your normal exercise for the 3 days prior to your test but avoid vigorous exercise in the 12 hours immediately prior to the test.
  • If you are taking any medication you should continue to take this, unless instructed otherwise by your health professional.
  • You will need to remain at  the Collection Centre for just over 2 hours.  During this time you will be required to rest.  You may like to bring a book to read.

Test Procedure

Please follow the guidelines listed below. This ensures accuracy of your test results. 

  1. The evening before your test, have your normal evening meal and supper (no later than 9.00pm).
  2. Do not eat or drink anything – other than water – from 9.00pm the evening before your test until you have had your test the following morning.
  3. On the morning of your test DO NOT eat breakfast.  You may drink water only until just before your test, but not during your test. 
  4. A blood sample will be collected.  You will then be given a drink containing 75gm of glucose.  You will be asked to drink this over a period of no more than 5 minutes.
  5. You should inform the staff if you feel unwell at any time during the test.
  6. A second blood sample will be collected 2 hours after you have finished the glucose drink. This completes your test – you may eat and drink normally after this.  

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Other languages

These instructions are available in other languages here.