Dexamethasone suppression test

This test measures cortisol before and after dexamethasone to check if your cortisol levels are under normal physiological control. In normal individuals, cortisol levels should be suppressed on the ‘post’ sample.

There are no dietary requirements for this test. You are required to make an appointment. For your nearest collection centre and to make an appointment, please refer to your request form, visit our Collection Centre Locations, or telephone Patient Services Support on 1300 732 030.

The test requires you to attend the Collection Centre at 9 am on two consecutive mornings. If your Doctor has not specified the dosage you will be given two tablets (1 mg of Dexamethasone) to take at 11 pm on the evening of the first day. The tablets should be stored in a cool dark place until taken. The collector will confirm with you, on the morning of the second day if you took the tablets at 11 pm, as required.

Dexamethasone can be upsetting to the stomach so should be taken with food or milk.

Note: If you have any allergies to any medications, especially steroids, please let the collector know as your test may need to be cancelled.

You may be required to perform a 24 hr urine collection as well. This needs to be collected prior to having the blood tests done. Your collector will be able to assist you with these instructions when you make your appointment.

Item number 34157 - Issue date November 2019