DefinitionAn ACTH test measures ACTH, a hormone released from the anterior pituitary gland in the brain.
Alternative NamesSerum adrenocorticotropic hormone; Adrenocorticotropic hormone; Highly-sensitive ACTH
How the test is performedA blood sample is needed. For information on how this is done, see: VenipunctureACTH levels change with the body's natural 24-hour cycle of processes (circadian rhythms). This test is most accurate if it is performed early in the morning.
How to prepare for the testThe health care provider may advise you to stop taking steroid drugs. You may need to be at the laboratory or office where the blood is being drawn by or before 8 a.m.
How the test will feelWhen the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performedThis test can help find the causes of hormone problems.The main function of ACTH is to regulate the steroid hormone cortisol, which is released by the adrenal cortex.
Normal ValuesNormal values: 9 - 52 pg/mLNote: pg/mL = picograms per milliliterThe examples above are common measurements for results for these tests. Some laboratories use different measurements or may test different specimens. Normal value ranges may vary slightly among different labs. Talk to your doctor about the meaning of your specific test results.
What abnormal results meanHigher-than-normal levels of ACTH may be present with:Addison's disease, when the adrenal glands do not produce enough cortisolCongenital adrenal hyperplasiaWhen the pituitary makes too much of the hormone ACTH (called Cushing's disease), which may be caused by excess growth of the pituitary gland, or tumors of the pituitary gland or elsewhere in the body (such as the pancreas, lung, and thyroid)Lower-than-normal levels of ACTH may be seen with:Pituitary gland that is not producing enough hormones, such as ACTHTumor of the adrenal gland that produces too much cortisolTumor elsewhere in the body that produces cortisolOther conditions under which the test may be performed:HypopituitarismMultiple endocrine neoplasia (MEN) I
What the risks areVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleedingFainting or feeling lightheadedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)
Special considerationsSpecial handling of the blood sample is required.
ReferencesStewart PM, Krone NP. The adrenal cortex. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 15.Melmed S, Kleinberg D. Pituitary masses and tumors. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 9.