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 healthcare provider make a diagnosis.

Why do I need this test?

You may need this test if your healthcare 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 healthcare 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?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

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

Licorice intake

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

Stress

Pregnancy

How do I get ready for this test?

Aldosterone levels are highest in the morning, so you may need to have the test in the morning after you’ve been awake and moving around for about 2 hours.

Ask your healthcare 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 healthcare 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.