Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
Birth control pills and some medicines can affect results.
Why it's done
- Signs of Cushing's, like weight gain in the face and belly, purple stretch marks, and high blood sugar
- An adrenal lump found on a scan
Getting ready and what happens
- Take the dexamethasone pill at 11 p.m.; blood is drawn the next morning around 8 a.m.
How the test is done
- A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.
What the results mean
Cortisol falls
Normal.
Cortisol stays high
Suggests Cushing's syndrome; more tests confirm it.
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related medicines
Related tests
Sources
Last updated 2026-11-13.