Synacthen Test

Print this article
Share this page:
Also known as: ACTH stimulation test, short synacthen test, SST
Related tests: ACTH, Cortisol

At a Glance

Why Get Tested?

To help diagnose Addison's disease. To assess adrenal and pituitary gland function.

When to Get Tested?

When a doctor suspects that the adrenal gland is not producing enough cortisol. When a doctor suspects that the pituitary gland is not producing enough adrenocorticotrophic hormone (ACTH).

Sample Required?

A blood sample is collected and then a small amount of synacthen is injected into a vein or muscle.  A further blood sample is taken after 30 minutes and/or 60 minutes.

Test Preparation Needed?

Exogenous steroids (glucocorticoids) should be stopped at least 24 hours before the test e.g. prednisolone, and inhaled steroids should not be taken the morning of the test. Those taking oestrogen replacement or the oral contraceptive containing oestrogen should ideally stop 6 weeks prior to the test (alternative forms of contraception should be used). Please discuss with your healthcare professional prior to the test being performed.