Your doctor has requested a low dose Dexamethasone suppression test. this test is used to see if your adrenal gland is producing excess Steroid hormone. Normally steroid hormones fromt he adrenal gland is under the control of the Pituitary gland. This test is designed to see if the control is intact.

Dexamethasone stops your body from producing steroid hormone ( Cortisol). This happens as the pituitary and hypothalamic signals to the adrenal gland are shut off temporarily after Dexamethasone .

  1. This test is used as a screening test to exclude Cushing’s Syndrome.
  2. This test can also be used to check for causes of hyperandrogenism ( Elevated Testosterone)congenital Adrenal Hyperplasia in women

If applicable..

It is important to stop all oestrogen therapy at least 6 weeks prior to test ( eg combined oral contraceptive pill, Menopausal hormone treatment). Please use alternate contraception.

Precautions

  1. Is there any chance you can be pregnant. IF in doubt, please inform your doctor
  2. Are you on Oestrogen containing products? ( Eg Pill, Menopausal hormone treatment) If so this needs to be stopped for 6 weeks
  3. If you are on steroids, (eg Prednisolone), This may need to be stopped for a short while before the test ( 2 – 3 days). Please discuss with your doctor first.

Side Effects

  1. Dexamethasone is well tolerated. It can interfere with sleep, occasional heartburn.. Please read the package insert leaflet. You do not need to worry about long term side effects like diabetes
  2. If you do have diabetes, this control may be upset for a couple of days. Please discuss with your doctor
  3. Your doctor may be able to do alternative tests. please discuss if you have concerns

Preparation for the test.

  1. This test takes place over 48 hours . Are you able to free up that time?
  2. book in for two blood tests ( 9 AM on Day 1 ) and 9 AM on Day 3
  3. Please get Dexamethasone tablets 0.5mg 8 tablets prior to the day of the test

 Procedure

 Day 1

  • 8:00 AM Come to hospital for blood test. Bring your first tablet of dexamethasone with you
  • 9:00 AM Blood test for ACTH and cortisol ( Transport to lab urgently for processing within 30 minutes of the sample being taken)
  • 9:05 AM, Take first tablet of Dexamethasone
  • You can now go back home or to work
  • 3 PM Tablet Dexamethasone 2nd tablet
  • 9 PM Tablet Dexamethasone 3rd Tablet
  • Set alarm for 3 AM before going to bed. This is really important

Day 2 

  • 3 AM Tablet Dexamethasone 0.5 mg oral 4th Tablet
  • 9 AM Tablet Dexamethasone 0.5 mg oral 5th Tablet
  • 3 PM Tablet Dexamethasone 0.5mg Oral 6th Tablet
  • 9 PM Tablet Dexamethasone 0.5mg oral 7th Tablet
  • Set alarm for 3 AM before going to bed. This is really important

Day 3

  •  3 AM Tablet Dexamethasone 0.5 mg oral 8th Tablet
  • 8AM come to hospital for blood test
  • 9 AM blood test for ACTH and Cortisol. Transport urgently to Lab

 

 Your results will be ready in 1 week. and your doctor will discuss this with you