What Is an Aldosterone Test?

What to expect before, during, and after this procedure

Woman receiving injection

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Aldosterone is a hormone that is produced by your adrenal glands, which are small, triangle-shaped glands situated at the top of your kidneys. A primary function of aldosterone is to control your blood pressure.

It does so by influencing other organs, like the kidneys, colon, and the urinary system, to regulate the amount of sodium and potassium in the bloodstream. When sodium is retained, water increases as well, resulting in a rise in blood volume and blood pressure.

An aldosterone test measures the amount of the hormone in your blood. Typically, the test is a blood test, but a 24-hour urine collection test can also be done depending on how your doctor wishes to measure your aldosterone levels.

Purpose of an Aldosterone Test

An aldosterone test may be ordered by your doctor for several reasons, including:

  • to measure the amount of aldosterone that is being secreted by your adrenal glands into your body
  • to look for the presence of a tumor that may be impacting the function of your adrenal glands
  • to evaluate the origins of high blood pressure or decreased potassium levels
  • to assess the severity of low blood when standing, a condition also known as orthostatic hypotension

Generally, an aldosterone test will be combined with other tests to diagnose conditions that may affect whether your body is over- or under-producing the hormone.

These other tests may include a renin hormone test or an ACTH (adrenocorticotropic hormone) stimulation test,

Risk and Contraindications

In most cases, a blood draw is a fairly easy procedure. However, every person’s veins are different, and some veins are more challenging to collect blood from than others. Although the risks associated with blood draws are low, the following are some minor incidents that can occur.

  • Bruising: Bruising at the site where the blood was obtained may occur. To reduce the likelihood of this happening, maintain pressure on the site as per the recommendations of the technician. 
  • Phlebitis: When blood is taken from a vein, they can become painful and inflamed, a condition known as phlebitis. If this occurs, you can usually ease the symptoms by holding a warm compress on it.
  • Infection: There’s a small chance an infection can occur when blood is drawn, though, the chances of it happening are very low.
  • Excessive bleeding: You may experience this at the site of injection.
  • Lightheadedness: You may feel faint or experience lightheadedness.
  • Hematoma: Blood can accumulate under the skin, causing a hematoma.

Before the Test

Certain drugs may interfere with the levels of aldosterone in your blood, so your doctor may ask you to stop some medications before the lab test is completed. Medications that can pose a problem include:

  • hormone replacement medications like corticosteroids, estrogen, and progesterone
  • heart medications such as diuretics, beta-blockers, and calcium channel blockers
  • pain medications, especially non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen
  • drugs used to treat too much stomach acid (antacids) or ulcers

Your doctor may also give you instructions on the amount of salt you can consume before the test. Sometimes, the test is done following an intravenous (IV) saline solution.

Additionally, lifestyle considerations, including pregnancy, activity level, stress, and diet can impact aldosterone levels, so your healthcare provider might give you specific guidelines to follow to obtain the most accurate results.

During the Test

If you’ve had blood drawn in the past, an aldosterone test will be done in a similar manner: The person drawing your blood may be a lab technician, a phlebotomist, a nurse, or a doctor. First, your healthcare provider will place an elastic band around your arm to compress the blood vessels, stop the flow of blood, and locate a vein.

Once the vein has been identified, they will insert a needle into it—if your veins are difficult to locate or move during the draw, it may need to be inserted more than once.

After the needle has been inserted into the vein, your healthcare provider will place a tube a the end of the needle to collect the sample. Once your provider has collected a sufficient amount of blood for the test, they’ll remove the elastic band, place pressure over the site of insertion with gauze or a cotton ball, and place an adhesive bandage on it.

If you haven’t had your blood drawn before, you might be anxious to know what it feels like when you’re poked with a needle. Some people experience a mild to moderate amount of pain upon the insertion of the needle. But other people may only feel a slight prick or close to nothing at all. One person’s experience with a blood test may be different than someone else’s. 

After the Test

After the blood test is finished, your provider may ask you to keep the bandage on for a specific amount of time. Usually, however, there are minimal follow-up instructions regarding an aldosterone blood test itself. If your physician suspects you have an illness, they might have particular instructions to follow while waiting for the test results to come back.

Depending on the lab and the day of the week you had your blood drawn, the results could take three to five days to return.

Interpreting the Results

Several factors impact how an aldosterone test can be interpreted, according to the National Institutes of Health, MedlinePlus. The online medical library states the results of the test may vary with age. Additionally, the range that’s considered normal may be different from one laboratory to the next.

An elevated level of aldosterone may indicate health conditions like Bartter syndrome and other kidney diseases, problems with the adrenal glands (such as a benign tumor), or a diet that is too low in sodium.

On the other hand, test results that demonstrate a decreased level of aldosterone may be indicative of an autoimmune condition known as Addison’s disease, a diet that contains an abundance of sodium in it, and more. Ultimately, your doctor will discuss your test results with you.

A Word From Verywell

When you receive your results, keep in mind that the reference range listed on the test serves as a guide to what may be going on inside your body. Your healthcare provider will consider many factors, like your health history and list of symptoms, when diagnosing you.

If you do end up having too much or too little aldosterone in your blood, there are several treatment options you’ll be able to consider (depending on the what’s causing the problem) to help you achieve a successful outcome. 

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