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Adrenocorticotropic Hormone (ACTH) Test

This test measures the level of adrenocorticotropic hormone (ACTH) in your blood. ACTH tells your adrenal glands to make cortisol, a hormone that affects stress, inflammation, blood sugar, metabolism, and blood pressure. The test helps diagnose and monitor conditions that affect cortisol levels, such as disorders of the pituitary and adrenal glands.

What this test measures

This test measures the level of adrenocorticotropic hormone (ACTH) in a sample of your blood. ACTH is a hormone that tells your adrenal glands to make another hormone called cortisol.

What your results mean

Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.

Higher-than-normal results

High ACTH and high cortisol levels are a sign of a pituitary tumor that makes ACTH (Cushing's disease). High ACTH and low cortisol levels are a sign of damage to your adrenal glands (Addison disease).

Lower-than-normal results

Low ACTH and high cortisol levels are a sign of Cushing's syndrome. Low or normal ACTH and low cortisol levels are a sign of hypopituitarism.

Frequently asked questions

What is ACTH?

ACTH stands for adrenocorticotropic hormone. It is a chemical messenger that tells your adrenal glands to make cortisol.

Why is ACTH tested with cortisol?

Because ACTH controls how much cortisol you make, the test is usually done with a cortisol test to help find out which condition may be causing abnormal cortisol levels.

What does high ACTH and high cortisol mean?

It may be a sign of Cushing's disease, which is a tumor in the pituitary gland that makes too much ACTH.

What does low ACTH and high cortisol mean?

It may be a sign of Cushing's syndrome, which can be caused by long-term use of steroid medicines or an adrenal gland tumor.

What does low ACTH and low cortisol mean?

It may be a sign of hypopituitarism, where the pituitary gland cannot make enough ACTH, so the adrenal glands do not make enough cortisol.

Related lab tests

Sources

Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.