Low dose overnight dexamethasone suppression test

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.

This test will help us to know if you might have Cushing’s syndrome. Cushing’s syndrome is a disease caused by excess cortisol production. Cortisol is a natural steroid hormone or chemical signal. It is produced by the adrenal glands, which are just above the kidneys, in response to instructions from the pituitary gland, which is a small gland beneath the brain. This test is also recommended as a routine investigation if you have a benign adrenal nodule (adrenal adenoma).

We will ask you to take a tablet at home at night, and then attend for a single blood test the following morning.

A nurse or phlebotomist (a health care professional trained to take blood) will take the blood test.

Your endocrinologist will give you a prescription for one dexamethasone tablet (1 mg) and a blood request form. You will need to collect the tablet from your pharmacy. You should take the tablet at 11pm at home, and then attend for a blood test to be taken at 9am the following morning. The timing of the tablet and the blood test is very important and needs to be as close to the recommended times as possible so that the results are accurate.

Dexamethasone is a steroid tablet that reduces the production of cortisol (the natural steroid hormone).

We will do one blood test.