Glucose Tolerance Test
(GTT)
You have been asked to have a Glucose Tolerance Test (GTT). This test measures how your
body copes with a measured amount of glucose. The test is usually carried out to look for
diabetes.
Before the test
You should have nothing to eat or drink (except water) for a minimum of 10 hours before the
test. For example, if you arrive for a blood test at 7.00am then you cannot eat or drink after
9.00pm the evening before the test. Water is allowed but not tea, coffee, milk or alcohol.
You should still take any regular medication, provided you only take it with water.
This test may be done by your GP or they may send you to a clinic for the test. See overleaf for
details.
Please arrive at the clinic no later than 1.00pm to ensure there is time to perform the test.
When you come for the test you must bring the request form given to you by your nurse or
doctor. Check that all of your details are correct and if they are incorrect, please tell the
phlebotomist.
During the test
The test starts with a sample of your blood being taken to check your fasting glucose level.
You will then be given a glucose solution and a beaker of water to drink.
You will then sit quietly for the next 2 hours. During this time, you may not eat, drink, chew or
smoke and must remain seated in the designated area. This is because some people feel
unwell during this time and also because the test will be made invalid if you are too active and
will have to be repeated. You may wish to bring something to read or do, as long as it is not
distracting to the other patients.
After 2 hours you need to have a second blood sample taken to check how you have responded
to the glucose solution.
The test is now finished and you may leave the hospital. You do not need to be accompanied
for this test but you should eat something before travelling home.
Side-effects
As with all blood tests, there is a small risk of bruising where the needle was inserted. Please
follow any instructions given to you by the phlebotomist to minimise this risk.
Alternative tests
Your doctor has recommended this test as being the best option.
An alternative would be for your doctor to measure HbA1c on a single blood sample although
this is not suitable for all patients. If you would like more information please speak to your
doctor.
The consequence of not having the test is that your doctor may not be able to make a diagnosis
or treat you.
Results
The results will be sent back to the doctor or nurse who asked you to come for this test and will
be available from them within 5 working days.
Clinic details
•
Clinic F at London Road Community Hospital
Telephone: 01332 265500, extension 54794
•
Phlebotomy Clinic at Ripley Hospital
Telephone: 01773 743456
•
Phlebotomy Clinic at Belper Clinic, Babington Hospital
Telephone: 01773 824171
•
Phlebotomy Clinic at Heanor Hospital
Telephone: 01773 710711
•
Some GP Surgeries
Reference Code: P1661/1236/11.2014/VERSION4
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permission in writing from the Patient Information Service, Derby Hospitals NHS Foundation Trust. (P1281/12.2012/V6)