Does this test have other names?

Aldosterone-renin ratio (ARR), plasma renin activity (PRA), plasma aldosterone

What is this test?

This test measures levels of the hormones aldosterone and renin in your blood.

Aldosterone and renin play important roles in the body. Aldosterone regulates your levels of potassium, sodium, and overall blood volume. High levels of aldosterone can result from a condition called primary aldosteronism (PA), which causes high blood pressure. PA is also known as hyperaldosteronism or Conn syndrome. It can lead to a variety of other health conditions.

A high level of aldosterone typically causes a dip in renin level. The aldosterone and renin test looks at the ratio between these two hormones to help your health care provider make a diagnosis.

Why do I need this test?

You may need this test if your provider suspects that you have a high aldosterone level or PA. Besides high blood pressure, high aldosterone levels can damage your heart and vascular system as well as your brain and kidneys.

What other tests might I have along with this test?

You may also have frequent blood pressure tests if you're at risk for PA. Your provider may do other blood tests to find the cause of high blood pressure or confirm the PA diagnosis.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your provider.

In general, a high level of aldosterone and a low level of renin may mean you have primary aldosteronism.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my test results?

A number of factors can affect your levels of aldosterone and renin. These include:

• Time of day the test is done.

• Activity level during the day.

• Posture (sitting or lying down) when the sample is taken.

• Sodium (salt) intake.

• Eating licorice.

• Certain medicines, such as water pills and medicines for high blood pressure.

• Stress.

• Pregnancy.

How do I get ready for this test?

Since aldosterone levels are highest in the morning, it is best to schedule the test during this time, after you have been awake and active for about 2 hours.

Ask your provider if you have any food restrictions and if you need to stop taking your medicine or avoid certain foods before the test. Be sure your provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.