Patients under the age of 16 or over the age of 60 or anyone suffering from epilepsy or angina should not have this test done.
What do I need to do before the test?
You must have nothing to eat from midnight on the night before the test. You may drink plain water only after midnight.
As the test measures your steroid levels you must not take your steroids (hydrocortisone or dexamethasone) after your lunchtime dose the day before your test.
What does the test involve?
The test involves the administration of insulin through a small needle called a cannula, which is placed in a vein in the crook of the arm. Blood samples will then be taken from this cannula to check the hormone levels following the administration of the insulin.
You will need an ECG to check your heartbeat and rhythm; this will be done just before the test.
How long will the test take?
The test will take approximately three hours to complete.
Side-effects
During the test you may experience side effects. The side effects can make you feel clammy, dizzy, sleepy and nauseous. This is a normal response to the test. These side effects are due to a drop in blood sugar levels, which is necessary to assess the response of your pituitary gland. Convulsions and palpitations are rare side effects which occur very infrequently. The side effects of the test only last during the time of the test and are soon resolved once you are given a sugary drink and something to eat, an injection of glucose can be given via the cannula should you need it.
We do not have facilities to provide food and drink so bring something with you for during the day.
An endocrinology specialist nurse will do the test. Medical support is available at any time during the procedure.
Following the test you are requested not to drive for two hours.
The results of this test will be reviewed by your Doctor and discussed at your next clinic appointment.