Talk to your doctor about your medicines before the test. Many drugs can affect ADH level, including:
Diuretics (water pills)
Blood pressure medicines
Mental condition medicines
How the Test will Feel
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.
Why the Test is Performed
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 gland, 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 health care provider suspects you have a disorder that affects your ADH level such as:
Buildup of fluids in your body that are causing swelling or puffiness (edema)
Excessive amounts of urine
Low sodium (salt) level in your blood
Thirst that is intense or uncontrollable
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 picograms per milliliter (pcg/mL).
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
A higher-than-normal levels 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).
Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.