Aldosterone and Renin
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?
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 healthcare
In general, a high level of aldosterone and a low level of renin may mean you have
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
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
Certain medicines, such as water pills and medicines for high blood pressure
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