Aldosterone Test
Reviewed
Also called: aldosterone, serum, aldosterone urine, aldosterone-renin ratio test, aldosterone-plasma renin activity
An aldosterone test measures the amount of aldosterone (ALD) in your blood or urine. ALD is a hormone made by your adrenal glands that helps keep your blood pressure stable by balancing sodium and potassium levels. This test is often combined with a renin test (aldosterone-renin ratio) to help diagnose adrenal gland disorders or find causes of abnormal blood pressure or electrolyte levels.
Specimen: Blood or urine
Why this test may be ordered
- To find out whether too much ALD is causing high blood pressure that occurs with low potassium, doesn't improve with usual medicines, or develops at a young age.
- To help diagnose adrenal gland disorders.
- To find the cause of abnormal sodium or potassium levels on an electrolyte test.
- To find the cause of orthostatic hypotension (low blood pressure causing dizziness when standing up).
Preparation and collection
Follow your provider's instructions. You may need to stop certain medicines and limit salt intake for about two weeks before the test. Do not eat natural black licorice for at least two weeks before the test.
Blood sample from a vein in your arm, or a 24-hour urine collection. For blood, you may be asked to lie down or stand for a period before the test. For urine, you will collect all urine over 24 hours.
Very little risk for blood test: slight pain or bruising at needle site, usually goes away quickly. No known risks for urine test.
Understanding results
Your provider will consider your aldosterone (ALD) levels along with the results of other tests to understand what your results say about your health.
- Higher than normal aldosterone levels: Higher than normal amounts of ALD may indicate primary aldosteronism (Conn syndrome, often due to a benign adrenal tumor) or secondary aldosteronism (healthy adrenal glands but another condition causing excess ALD, such as kidney disease, cirrhosis, heart failure, preeclampsia, or dehydration). Limitation: A screening result is not diagnostic by itself; further evaluation is needed. Next step: Your provider may order additional tests to confirm the cause.
- Lower than normal aldosterone levels: Lower than normal amounts of ALD may indicate Addison disease (adrenal insufficiency), congenital adrenal hyperplasia, secondary or tertiary adrenal insufficiency (e.g., from suddenly stopping steroid medicines), or Liddle syndrome. Low levels may also be linked to other conditions (e.g., diabetes, lead poisoning) or certain medicines (e.g., NSAIDs, some heart failure medicines). Limitation: A screening result is not diagnostic by itself; further evaluation is needed. Next step: Your provider may order additional tests to identify the underlying condition.
- Results must be interpreted together with other tests (e.g., renin, electrolytes).
- Levels change with posture (lying vs. standing).
- Certain medicines, salt intake, and natural black licorice can affect results.
What to do next
Your provider will consider your aldosterone levels along with other test results to determine what your results mean for your health.
- What do my aldosterone test results mean in combination with my other test results?
- Do I need to adjust my medicines or diet before the test?
- What follow-up tests or steps are recommended based on my results?