Aldosterone in Blood
An aldosterone test measures the level of
hormone made by the
adrenal glands), in the blood. Aldosterone helps
potassium levels in the body. This helps control blood
pressure and the balance of fluids and
electrolytes in the blood.
renin normally stimulates the adrenal glands to
release aldosterone. High levels of both renin and aldosterone are normally
present when the body is trying to conserve fluid and salt (sodium). When a
tumor that makes aldosterone is present, your aldosterone level will be high
while a renin level will be low. Usually a renin activity test is done when the
aldosterone level is measured.
Why It Is Done
An aldosterone test is done to:
- Measure the amount of aldosterone released into
the body by the adrenal glands.
- Check for a tumor in the adrenal
- Find the cause of high blood pressure or low blood
potassium levels. This is done when overactive adrenal glands or an abnormal
adrenal growth are suspected.
How To Prepare
An aldosterone test is often done at the
time of a routine blood test. You do not need to do anything before having
routine blood tests.
If you are having follow-up aldosterone blood
tests, your doctor may give you the following instructions:
- Eat foods with a normal amount of sodium (2,300
mg per day) for 2 weeks before the test. Do not eat
foods that are very salty, such as bacon, canned soups and vegetables, olives,
bouillon, soy sauce, and salty snacks like potato chips or pretzels. A low-salt
diet can also increase aldosterone levels. Tell your doctor if you are on a
low-salt food plan.
- Do not eat natural black licorice for 2 weeks before this
Many medicines may change the results of this test. Be sure
to tell your doctor about all the
nonprescription and prescription medicines you take.
You may be asked to stop taking some medicines for 2 weeks before the test.
These include hormones (such as progesterone and
diuretics, and many medicines used to treat high blood
pressure, especially spironolactone (Aldactone), eplerenone (Inspra), and
The amount of aldosterone
in blood changes depending on whether you are standing up or lying down. If
initial results show a problem, repeat tests may be done in different positions
and under different conditions, such as not eating before the test or eating
foods that contain a specific amount of salt. Your doctor may ask you to have
your blood drawn at a certain time because aldosterone levels are highest in
the early morning.
Talk to your doctor about any concerns you have
regarding the need for the test, its risks, how it will be done, or what the
results will mean. To help you understand the importance of this test, fill out
medical test information form(What is a PDF document?).