Antidiuretic blood test measures the level of antidiuretic hormone (ADH) in blood.
A blood sample is needed.
Talk to your health care provider about your medicines before the test. Many drugs can affect ADH level, including:
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.
ADH is a hormone that is produced in a part of the brain called the hypothalamus. It is then stored and released from the pituitary, a small gland at the base of the brain. ADH acts on the kidneys to control the amount of water excreted in the urine.
ADH blood test is ordered when your provider suspects you have a disorder that affects your ADH level such as:
Certain diseases affect the normal release of ADH. The blood level of ADH must be tested to determine the cause of the disease. ADH may be measured as part of a water restriction test to find the cause of a disease.
Normal values for ADH can range from 1 to 5 pg/mL (0.9 to 4.6 pmol/L).
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your provider about the meaning of your specific test results.
A higher-than-normal level may occur when too much ADH is released, either from the brain where it is made, or from somewhere else in the body. This is called syndrome of inappropriate ADH (SIADH).
Causes of SIADH include:
A lower-than-normal level may indicate:
Veins and arteries vary in size from one person 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:
Reviewed By: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.