Also Known As
Antidiuretic Hormone
Vasopressin
Arginine Vasopressin
AVP
Formal Name
Antidiuretic Hormone; Arginine Vasopressin
This article was last reviewed on
This article waslast modified on
25 May 2018.
At a Glance
Why Get Tested?

To help detect, diagnose, and determine the cause of antidiuretic hormone (ADH) deficiency or excess. However, this test is not widely used; diagnoses of conditions of ADH excess/ deficiency are usually based on clinical history and other laboratory tests, such as blood and urine osmolality as well as electrolytes.

When To Get Tested?

ADH may be requested if results of initial investigations of ADH deficiency/ excess are equivocal. However, ADH analysis is rarely required.

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

Alcohol and some medications (including diuretics) can interfere with ADH secretion or its action. Talk to your doctor to identify any medications that should be discontinued before the test.

An ADH test may be requested as part of a water deprivation test. Talk to your doctor to determine if any preparation is required for this test.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you will be able to access your results online.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

The ADH test measures the amount of antidiuretic hormone (ADH) in the blood. ADH, also called arginine vasopressin (AVP), is a hormone produced by the hypothalamus and stored in the posterior pituitary gland. Antidiuretic hormone helps regulate water balance in the body by controlling the amount of water the kidneys reabsorb.

ADH is normally released by the pituitary in response to sensors that detect increases in blood osmolality or decreases in blood volume. The kidneys react to ADH by conserving water and producing urine that is more concentrated. The retained water dilutes the blood, lowers its osmolality, and increases blood volume and pressure. If this is not sufficient to restore the water balance, then thirst is also stimulated so that the affected person will drink more water.

There are a variety of disorders, conditions, and medications that can affect either the amount of ADH released or the kidneys' sensitivity to it. ADH deficiency and excess can cause acute and chronic symptoms that, in rare cases, may become life-threatening. If there is too little ADH or the kidneys do not respond to ADH, then too much water is lost through the kidneys, the urine produced is more dilute than normal, and the blood becomes more concentrated. This can cause excessive thirst, frequent urination, dehydration, and high blood sodium (hypernatraemia). If there is too much ADH, then water is retained, blood volume increases, and the person may experience nausea, headaches, disorientation, lethargy, and hyponatraemia.

The ADH test is not widely used to diagnose these conditions. Often, a diagnosis is made on the basis of clinical history and other laboratory tests such as urine and blood osmolality and electrolytes.

ADH deficiency is called diabetes insipidus. There are two types of this disorder: central and nephrogenic. Central diabetes insipidus is associated with a lack of ADH production by the hypothalamus or release from the pituitary and may be due to a variety of causes, including an inherited genetic defect, head trauma, a brain tumour, or due to an infection that causes encephalitis or meningitis. Nephrogenic diabetes insipidus originates in the kidney and is associated with a lack of response to ADH, causing an inability to concentrate urine. It may be inherited or caused by a variety of kidney diseases. Both types of diabetes insipidus lead to the excretion of large quantities of dilute urine.

Increased concentrations of ADH are often seen with "syndromes of inappropriate antidiuretic hormone" (SIADH). SIADH is characterised by production of too much ADH, resulting in water retention, hyponatraemia, and decreased blood osmolality. It may be due to a wide number of diseases and conditions that either i) stimulate excessive ADH secretion or ii) prevent its suppression. SIADH may also be seen with cancers that produce ADH or ADH-like substances independent of the hypothalamus and pituitary glands. Regardless of the cause or source, excessive ADH causes low blood sodium and osmolality because water is retained and blood volume is increased.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

Alcohol and some medications (including diuretics) can interfere with ADH secretion or its action. Talk to your doctor to identify any medications that should be discontinued before the test.

An ADH test may be requested as part of a water deprivation test. Talk to your doctor to determine if any preparation is required for this test.

Accordion Title
Common Questions
  • How is it used?

    The antidiuretic hormone (ADH) test may be requested by itself or along with or following other tests to help detect, diagnose, and determine the cause of antidiuretic hormone deficiencies and excesses. However, this test is not widely used; diagnoses of these conditions are often based on clinical history and other laboratory tests, such as blood and urine osmolality as well as electrolytes.

    Symptoms of ADH deficiency are often seen with one of two types of diabetes insipidus. Central diabetes insipidus is a decrease in the production of ADH by the hypothalamus or in the release of ADH from the pituitary; nephrogenic diabetes insipidus is characterised by a decrease in the kidney's response to ADH. A water deprivation test is the preferred means to diagnose diabetes insipidus and distinguish between the central and nephrogenic forms. The test involves collection of several timed urine and blood samples for osmolality analysis during strictly controlled fluid restriction and after administration of synthetic ADH (ddAVP). This procedure must be performed under close medical supervision as it can sometimes lead to severe dehydration and can pose a risk to some people with underlying diseases. If the results of the initial water deprivation test are equivocal, then the test may be repeated and additional samples obtained for ADH analysis at defined intervals. The levels of ADH obtained are used to determine if there is an appropriate ADH response to water deprivation.

    Symptoms of increased levels of ADH are often seen with "Syndromes of Inappropriate ADH production" or SIADH. Testing for SIADH may include blood and urine osmolality, blood and urine sodium, and tests to exclude poor renal or adrenal function. Measurement of ADH for the diagnosis of SIADH is only required in exceptional circumstances.

  • When is it requested?

    An ADH test is not requested routinely. The ADH test may sometimes be required to help investigate hyponatraemia and its associated symptoms, and to identify SIADH If a diagnosis of diabetes insipidus is suspected then ADH may be requested as part of a water deprivation test

  • What does the test result mean?

    ADH test results alone are not diagnostic of a specific condition. The results are usually evaluated in conjunction with a person's medical history, physical examination, and results of other tests. Excesses and deficiencies of ADH may be temporary or persistent, acute or chronic, and may be due to an underlying disease, an infection, an inherited condition, due to a surgery or trauma, or even due to a psychological problem that leads to excess water drinking.

    Increased ADH concentrations are often associated with SIADH and may be seen with a variety of cancers, including leukaemia, lymphoma, lung cancer, pancreatic, bladder, and brain cancer. Greatly increased concentrations of ADH may be seen with systemic cancers that produce ADH. Moderate increases in ADH may be seen with nervous system disorders such as Guillain-Barré syndrome, multiple sclerosis, epilepsy, acute intermittent porphyria, with pulmonary disorders such as cystic fibrosis, emphysema, and tuberculosis, and in those with HIV/AIDS. The ADH test may sometimes be requested to help investigate hyponatraemia and its associated symptoms, and to identify SIADH, but it is not generally required to diagnose or monitor any of the diseases or conditions that may cause it.

    A low ADH result may be seen with central diabetes insipidus, compulsive water drinking, and with low serum osmolality. An increased ADH concentration may be seen in nephrogenic diabetes insipidus, with dehydration, trauma, and surgery.

    With ADH stimulation tests, such as the water deprivation test, a doctor is looking for appropriate concentrations of ADH, osmolality, and kidney water retention responses.

    • A water deprivation ADH stimulation test may be used to differentiate between the two types of diabetes insipidus.
      • Central diabetes insipidus is characterised by abnormally low production of ADH and the inability to concentrate urine that is reflected as an increase in urine osmolality after ADH administration but not an increase due to water deprivation alone.
      • Nephrogenic diabetes insipidus is the kidney's inability to respond to ADH that is reflected as no change in urine osmolality before or after ADH administration.
  • Is there anything else I should know?

    In general, the ability to concentrate urine decreases with age.

    ADH secretion increases when a person is standing, at night, and with pain, stress and exercise. Secretion decreases with hypertension and when someone is lying down.

    Many drugs can affect ADH levels. They include:

    • Drugs that stimulate ADH release, such as: barbiturates, desipramine, histamine, morphine, nicotine, amitriptyline and carbamazepine.
    • Drugs that promote ADH action, such as: acetaminophen, metformin, tolbutamide, aspirin, theophylline, and non-steroidal anti-inflammatory drugs.
    • Drugs that decrease ADH or its effects, such as: ethanol, lithium, and phenytoin.
  • Should everyone have an ADH test?

    No, for most people, ADH is appropriately produced and utilised by the body to maintain water balance. The ADH test is not used as a general screening test and most people will never have one done.

  • Can the ADH test be performed at my GP practice?

    No. Samples for ADH need to reach the laboratory very quickly. ADH is unstable in the withdrawn blood therefore the serum must be separated from the blood cells and frozen as soon as possible. Only a few laboratories offer ADH analysis and so the sample may need to be sent to a reference laboratory. If you have a water deprivation it will be performed under medical supervision.

  • How is diabetes insipidus different than diabetes mellitus?

    Diabetes mellitus, usually referred to as diabetes, is related to either decreased insulin production or insulin resistance and causes an increase in blood glucose. Diabetes insipidus is not related to insulin or glucose, but both diabetes conditions can cause increased thirst and frequent urination.

  • Can diabetes insipidus be treated?

    Yes, a synthetic form of ADH can be given as a replacement to those with central diabetes insipidus. Those with nephrogenic diabetes insipidus are encouraged to drink adequate amounts of water to replace what is being lost in their urine and should talk to their doctor about possible adjustments to their diet.