Diseases & Conditions


Overview & Description

This test measures the amount of adrenocorticotropic hormone, known as ACTH, in the blood. ACTH is a hormone made by the pituitary gland. It regulates the production and secretion of the hormone cortisol by the adrenal gland.

Who is a candidate for the test?

This test is normally performed on persons with whose hormone levels are not in a healthy range. A doctor may suspect a link with problems in the pituitary gland or the adrenal gland.

How is the test performed?

To measure ACTH levels, a blood sample is taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube called a tourniquet is wrapped around the upper arm. This restricts blood flow in the veins in the lower arm and enlarges them. A fine needle is inserted into a vein, and the tourniquet is removed. Blood flows from the vein through the needle and is collected in a vial for testing in the laboratory. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding.

Preparation & Expectations

What is involved in preparation for the test?

The doctor will provide specific instructions. Generally, no preparation is required.

Results and Values

What do the test results mean?

Healthy levels of ACTH in the blood may range from 0 to 100 pg/mL (picograms per milliliter).

High levels of ACTH may be caused by:

  • a slowdown in functioning of the adrenal glands, such as Addison disease
  • pituitary gland tumor, which is an abnormal growth in the pituitary gland
  • other tumors that produce excess ACTH
  • Low levels of ACTH can be caused by:

  • excess production of cortisol by the adrenal glands, which occurs in conditions such as Cushing syndrome
  • certain tumors of the adrenal gland
  • various diseases of the pituitary gland

  • Attribution

    Author:David T. Moran, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:06/28/02
    Reviewer:Adam Brochert, MD
    Date Reviewed:09/20/01