Antidiuretic Hormone (ADH) Test: Definition And Patient Education

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HealthlineSubscribeAntidiuretic Hormone (ADH) Test

Medically reviewed by Elaine K. Luo, M.D. — Written by Sandy Calhoun Rice — Updated on September 29, 2018

What is ADH?
Purpose
Test procedure
Preparation
Risks
Results
Follow-up

ADH helps your body regulate the water content of your blood, which impacts blood pressure and volume. Unusually high or low levels of ADH can indicate an underlying condition requiring treatment.

Antidiuretic hormone (ADH) is a hormone that helps your kidneys manage the amount of water in your body. The ADH test measures how much ADH is in your blood. This test is often combined with other tests to find out what is causing too much or too little of this hormone to be present in the blood.

What is ADH?

ADH is also called arginine vasopressin. It’s a hormone made by the hypothalamus in the brain and stored in the posterior pituitary gland. It tells your kidneys how much water to conserve.

ADH constantly regulates and balances the amount of water in your blood. Higher water concentration increases the volume and pressure of your blood. Osmotic sensors and baroreceptors work with ADH to maintain water metabolism.

Osmotic sensors in the hypothalamus react to the concentration of particles in your blood. These particles include molecules of sodium, potassium, chloride, and carbon dioxide. When particle concentration isn’t balanced, or blood pressure is too low, these sensors and baroreceptors tell your kidneys to store or release water to maintain a healthy range of these substances. They also regulate your body’s sense of thirst.

Purpose of ADH level testing

The normal range for ADH is 1-5 picograms per milliliter (pg/mL). Normal ranges can vary slightly among different laboratories. ADH levels that are too low or too high can be caused by a number of different problems.

ADH deficiency

Too little ADH in your blood may be caused by compulsive water drinking or low blood serum osmolality, which is the concentration of particles in your blood.

A rare water metabolism disorder called central diabetes insipidus is sometimes the cause of ADH deficiency. Central diabetes insipidus is marked by a decrease in either the production of ADH by your hypothalamus or the release of ADH from your pituitary gland.

Common symptoms include excessive urination, which is called polyuria, followed by extreme thirst, which is called polydipsia.

People with central diabetes insipidus are often extremely tired because their sleep is frequently interrupted by the need to urinate. Their urine is clear, odorless, and has an abnormally low concentration of particles.

Central diabetes insipidus can lead to severe dehydration if it’s left untreated. Your body won’t have enough water to function.

This disorder is not related to the more common diabetes, which affects the level of the hormone insulin in your blood.

Excess ADH

When there’s too much ADH in your blood, syndrome of inappropriate ADH (SIADH) may be the cause. If the condition is acute, you may have a headache, nausea, or vomiting. In severe cases, coma and convulsions can occur.

Increased ADH is associated with:

leukemia
lymphoma
lung cancer
pancreatic cancer
bladder cancer
brain cancer
systemic cancers that produce ADH
Guillain-Barré syndrome
multiple sclerosis
epilepsy
acute intermittent porphyria, which is a genetic disorder that affects your production of heme, an important component of blood
cystic fibrosis
emphysema
tuberculosis
HIV
AIDS

Dehydration, brain trauma, and surgery can also cause excess ADH.

Nephrogenic diabetes insipidus is another very rare disorder that may affect ADH levels. If you have this condition, there’s enough ADH in your blood, but your kidney can’t respond to it, resulting in very dilute urine. The signs and symptoms are similar to central diabetes insipidus. They include excessive urination, which is called polyuria, followed by extreme thirst, which is called polydipsia. Testing for this disorder will likely reveal normal or high ADH levels, which will help distinguish it from central diabetes insipidus.

Nephrogenic diabetes insipidus is not related to the more common diabetes mellitus, which affects the level of insulin hormone in the blood.

How the blood sample is taken

A healthcare provider will draw blood from your vein, usually on the underside of the elbow. During this process, the following occurs:

The site is first cleaned with an antiseptic to kill germs.
An elastic band is wrapped around your arm above the potential area of the vein where the blood will be drawn. This causes the vein to swell with blood.
Your healthcare provider gently inserts a needle syringe into your vein. Blood collects in the syringe tube. When the tube is full, the needle is then removed.
The elastic band is then released, and the needle puncture site is covered with sterile gauze to stop the bleeding.

How to prepare for your blood test

Many medications and other substances can affect the levels of ADH in your blood. Before the test, your doctor may ask you to avoid:

alcohol
clonidine, which is a blood pressure medication
diuretics
haloperidol, which is a medication used to treat psychotic and behavioral disorders
insulin
lithium
morphine
nicotine
steroids

Potential risks from undergoing an ADH test

The uncommon risks of blood tests are:

excessive bleeding
fainting
lightheadedness
blood pooling under the skin (a hematoma)
infection at the puncture site

Understanding your test results

Abnormally high levels of ADH may mean you have:

a brain injury or trauma
a brain tumor
a brain infection
a central nervous system infection or tumor
a lung infection
small cell carcinoma lung cancer
fluid imbalance after surgery
syndrome of inappropriate ADH (SIADH)
a stroke
nephrogenic diabetes insipidus, which is very rare
acute porphyria, which is very rare

Abnormally low levels of ADH may mean:

pituitary damage
primary polydipsia
central diabetes insipidus, which is rare

Following up after the test

An ADH test alone is usually not enough to make a diagnosis. Your doctor will probably need to perform a combination of tests. Some tests that may be performed with an ADH test include the following:

Anosmolality test is a blood or urine test that measures the concentration of dissolved particles in your blood serum and urine.
An electrolyte screening is a blood test that’s used to measure the amount of electrolytes, usually sodium or potassium, in your body.
A water deprivation testexamines how frequently you urinate if you stop drinking water for several hours.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

ADH.(2014).http://labtestsonline.org/understanding/analytes/adh/tab/test
Diabetesinsipidus - diagnosis. (2014).http://www.nhs.uk/Conditions/Diabetes-insipidus/Pages/Diagnosis.aspx
Osmolality.(2013).http://labtestsonline.org/understanding/analytes/osmolality

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Medically reviewed by Elaine K. Luo, M.D. — Written by Sandy Calhoun Rice — Updated on September 29, 2018

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