Growth Hormone Response To An Oral Glucose Tolerance Test

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Why do I need this text?

Your doctor has recommended that you take this test to help with the diagnosis and the management of your condition.

Please would you read this carefully and ask us about anything that is not clear or if you would like more information.

What is the purpose of the test?

This test is used to check your production of a chemical messenger called growth hormone. It helps in the diagnosis and follow-up of patients with acromegaly, a condition caused by excess production of growth hormone by the pituitary gland (at the base of the brain).

How long will the test take?

The test will take just over 2 hours in total.

Who will carry out the test?

The test will be carried out by an endocrine specialist nurse or a phlebotomist (a health care professional trained to take blood).

What will I have to do?

Please have nothing to eat or drink except water or black tea /coffee (no milk or sugar) for 10 hours before the test.

Is any drug or medicine used during the test?

We will give you a measured amount of a glucose drink, such as Lucozade.

What will happen during the test?

The nurse or phlebotomist may use a needle to insert a small plastic tube into a vein in your arm. We will use this to take blood samples without any more needles. After we have taken the first blood sample, we will give you the glucose drink (such as Lucozade). We measure your response to the test by taking more blood samples every 30 minutes for two hours. After this you are free to go home.

What are the possible risks or side-effects of the test?

None.

What are the alternatives to the test?

It can be difficult to diagnose Cushing’s syndrome. A number of different tests may be necessary, including blood tests, urine tests and scans. This varies from patient to patient, and depends on the results of your investigations. Your endocrinologist will advise you about this in more detail.

What will happen after the test?

We will send your blood samples to the laboratory for analysis. When your results are available, either the endocrine specialist nurse or your endocrinologist will discuss these with you. This will usually be at your next clinic appointment. They will advise you about other tests you might need.

Who do I contact if I have any questions?

If you have any urgent or emergency questions then your GP can advise you or they will contact the hospital on your behalf.

Patient self-help groups and further information: The Pituitary Foundation.