ACTH (adrenocorticotropic hormone) blood test
Quick answer: An ACTH test measures the pituitary hormone that tells the adrenal glands to make cortisol. It is usually ordered with cortisol to work out the cause of too much or too little cortisol, as in Cushing's syndrome or Addison's disease.
- SampleBlood
- TakesAbout 5 minutes, usually in the early morning
- Before the testAn early-morning sample is usually needed; follow the timing your doctor gives.
How the test is done
- 1You arrive early in the morning, as your doctor has advised
- 2You may rest for a short while before the sample
- 3Blood is drawn into a chilled tube
- 4The sample is kept cold and taken to the lab quickly
What your results can mean
Reading your report
Hormone ranges differ between labs and by age, sex and cycle day, so discuss your result with your doctor.
If the result is outside the usual range
A high level with low cortisol can point to a problem in the adrenal glands, such as Addison's disease. A low level with high cortisol can point to an adrenal cause of Cushing's syndrome, and a high level with high cortisol to a pituitary cause.
Who usually has this test
People with symptoms of too much or too little cortisol, such as weight gain with stretch marks, or tiredness, weight loss and low blood pressure.
Risks and aftercare
A small bruise can appear at the needle site, and you can eat and go about your day afterwards.
Names and options
Also called: ACTH, corticotropin
Listed by the hospital as
- ACTH, PLASMA
Questions about this test
Why is ACTH usually tested with cortisol?
ACTH and cortisol control each other. Looking at both together helps your doctor find whether a problem starts in the pituitary gland or in the adrenal glands.
Why does the ACTH sample need to be kept cold?
ACTH breaks down quickly at room temperature. Collecting it in a chilled tube and getting it to the lab fast helps prevent a falsely low result.
Do steroid medicines affect the ACTH test?
Yes. Steroid tablets, creams, inhalers or injections can lower ACTH. Tell your doctor about any steroids you use, but do not stop them on your own.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.