Antidiuretic hormone blood test

What's an Antidiuretic Hormone (ADH) Blood Test?

An antidiuretic hormone (ADH) blood test measures the amount of antidiuretic hormone in the blood. Antidiuretic hormone helps regulate the body’s water levels. It is released when the body has too much water, and it helps the kidneys reabsorb more water and reduce the amount of urine produced. The test is used to diagnose hormone deficiencies and dehydration.

Preparation

No special preparation is needed for an antidiuretic hormone (ADH) blood test. The healthcare provider may direct you to fast for eight hours before the test.

Procedure

During the test, a healthcare provider will take a small amount of blood from a vein. The procedure is quick and relatively painless. The blood is then sent to a laboratory for analysis.

Types

The two types of antidiuretic hormone (ADH) tests are Vasoactive Intestinal Peptide (VIP) or Arginine Vasopressin (AVP) tests. The Vip test measures the levels of vasoactive intestinal peptide, a hormone released by the pituitary gland which helps the body’s water levels. The AVP test measures the levels of arginine vasopressin, a hormone released by the pituitary gland in response to dehydration.

Risks

There are few risks associated with an antidiuretic hormone (ADH) blood test. The most common is discomfort or pain from the needle stick or from the tape used to secure the needle. The skin around the injection site may also become irritated or bruised.

Why it's done

An antidiuretic hormone blood test is used to evaluate hormone deficiencies and diagnose conditions such as diabetes insipidus (DI), a disorder caused by the pituitary gland or hypothalamus not producing enough ADH. It can help healthcare providers diagnose and treat dehydration or other medical conditions.

When to get tested

An antidiuretic hormone (ADH) blood test may be ordered when someone is having symptoms of dehydration, such as excessive thirst, frequent urination, and weakness. It may also be ordered as part of an evaluation of a glandular disorder, especially if symptoms of polyuria (excessive urine output) are present.