A blood sample is needed. For information on how this is done, see: Venipuncture
ACTH 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 test
The 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 feel
When 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 performed
This 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 values: 9 - 52 pg/mL
Note: pg/mL = picograms per milliliter
The 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 mean
Higher-than-normal levels of ACTH may be present with:
When 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 ACTH
Veins 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:
Fainting or feeling lightheaded
Hematoma (blood accumulating under the skin)
Infection (a slight risk any time the skin is broken)
Special handling of the blood sample is required.
Stewart 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.
Nancy J. Rennert, MD, Chief of Endocrinology & Diabetes, Norwalk Hospital, Associate Clinical Professor of Medicine, Yale University School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.