ACTH Test

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Also known as: Adrenocorticotropic hormone; corticotropin
Related tests: Cortisol; Synacthen stimulation test; dexamethasone suppression test

At a Glance

Why Get Tested?

To diagnose adrenal and pituitary diseases such as Cushing's syndrome, Cushing’s disease, Addison’s disease, adrenal tumours, and pituitary tumours; usually done as a diagnostic test once an abnormal cortisol level is detected

When to Get Tested?

If your doctor has discovered that you have abnormal cortisol levels.  ACTH will help to sort out the possible cause of the abnormal cortisol result.

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

The sample is unstable so needs to be collected in a hospital that has laboratory facilities to process it immediately. It cannot usually be collected at a GP surgery. Typically it is taken in the morning, about 9 am.

The Test Sample

What is being tested?

Adrenocorticotropic hormone (ACTH) is a hormone produced in the pituitary gland (located below the brain within the skull) to stimulate secretion of the hormone cortisol by the adrenal glands (small organs located at the top of each kidney). Stress can stimulate the release of ACTH. Cortisol is important for regulating glucose, protein, and lipid metabolism; suppressing the immune response; and maintaining blood pressure. Normally, ACTH concentration increases when cortisol is low and falls when cortisol is high.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

The sample is unstable so needs to be collected in a hospital that has laboratory facilities to process it immediately. It cannot usually be collected at a GP surgery. Typically it is taken in the morning, about 9 am.

The Test

Common Questions

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.