Aldosterone Test

An aldosterone test measures the amount of aldosterone (ALD) in your blood or urine (pee). ALD is a hormone made by your adrenal glands, two small glands that sit above your kidneys. ALD helps keep your blood pressure stable.

It does this by helping to balance the levels of two electrolytes in your blood, sodium and potassium. If your blood pressure gets too low, ALD signals your kidneys to release more sodium into your blood and to get rid of potassium through urine. This helps keep more water in your bloodstream, which makes your blood pressure increase.

When your blood pressure returns to normal, your ALD levels decrease. Abnormal ALD levels can cause serious health conditions, including: High blood pressure; Low blood pressure; Complications from abnormal levels of sodium and potassium, which can affect your heart, kidneys and other parts of your body; ALD testing may be used with other tests to help diagnose adrenal gland disorders. It can also help find out if other medical conditions are affecting the way your adrenal glands work.

An ALD test is commonly combined with a test that measures renin levels in your blood. This is called an aldosterone-renin ratio test. Renin is a hormone that your kidneys make when your blood pressure gets too low.

It's part of a complex system that triggers your adrenal glands to make ALD. Comparing renin and ALD levels helps show whether abnormal levels of ALD are caused by a problem with your adrenal glands or a problem with your kidneys or other parts of the system that triggers the production of ALD.

Why this test is done

You may need this test if your health care provider thinks you may have too much or too little aldosterone (ALD).

Signs and symptoms of too much ALD (called hyperaldosteronism or aldosteronism) include:

• High blood pressure
• Low potassium test results and/or high sodium test results
• Muscle weakness, cramps, and/or spasms
• Fatigue
• Headache
• Arrhythmia (a problem with the rate or rhythm of your heartbeat)
• Increased thirst and urination

Signs and symptoms of too little ALD (called hypoaldosteronism) include:

• Low blood pressure
• Test results that show high potassium and/or low sodium levels
• Fatigue
• Muscle weakness
• Loss of appetite
• Weight loss
• Abdominal (belly) pain

How to prepare

Follow the instructions your provider gives you. You may need to stop taking certain medicines for a period of time before the test. This includes certain over-the-counter medicines.

So, be sure to tell your provider everything you're taking. But don't stop taking any prescribed medicine unless your provider tells you to stop.

You may also be asked to limit the amount of salt you eat each day for about two weeks before your test. Your provider will explain how to limit salt in your diet.

You should not eat natural black licorice for at least two weeks before your test, because it can affect your results. Most licorice products in the United States don't contain natural licorice. But if you eat licorice, check the ingredients label to be sure.

Sample type

Blood Urine

Other names for this test

aldosterone, serum; aldosterone urine; aldosterone-renin ratio test; aldosterone-plasma renin activity