Why Do You Need an Aldosterone Test?

Addison’s disease. When your body doesn’t make enough of the hormone cortisol, it often doesn't make enough aldosterone either. When this happens, you can have:

• Low blood pressure
• Higher potassium levels
• An overall feeling of exhaustion

It can happen when there is damage to your adrenal glands.

Secondary hyperaldosteronism. It happens when your body makes more aldosterone in response to problems with other organs, such as your kidneys, heart, or liver.

It can cause things such as:

• High blood pressure
• Low potassium
• Fluid retention
• Exhaustion
• Muscle weakness
• Headache

Why Might You Need to Test Your Aldosterone Levels?

Here are some symptoms that indicate the need to have your aldosterone levels checked:

• Hard-to-control blood pressure levels
• Low blood pressure when you stand up 
• High or low blood sodium
• Heart problems, such as irregular heartbeat or atrial fibrillation
• Kidney abnormalities
• Low potassium levels, which can cause muscle weakness, paralysis, cramps, or spasms, frequent urge to pee, increased thirst, tiredness, headaches, and tingling and/or numbness in your hands and feet

Aldosterone Test Preparation

Your aldosterone levels can be measured with a simple blood test. You won't need to do anything special to prepare. 

But your doctor may decide to run follow-up aldosterone blood tests. In that case, you may need to follow instructions beforehand. Your doctor may tell you to avoid eating certain foods (like those high in sodium and natural black licorice) or stop taking some medicines (such as diuretics and beta-blockers) in the weeks before your test.

Aldosterone Test Procedure

Your doctor needs to take a small blood sample to measure your aldosterone level. A clinician will draw your blood through a needle inserted into a vein. You might feel a pinch or stinging during the test and have slight bruising afterward.

Aldosterone Test Results

When your doctor orders an aldosterone test, they may also ask for blood tests for cortisol and another hormone called renin. The results can help tell your doctor if you have certain disorders:

• If your tests show a high level of aldosterone, a low level of renin, and a normal cortisol level, your doctor may diagnose you with Conn's syndrome or hyperaldosteronism.
• If your results show a high level of aldosterone and a high level of renin, you may have secondary hyperaldosteronism.
• If your aldosterone and cortisol levels are lower than normal, and your renin level is high, you may be diagnosed with Addison’s disease.
• If your aldosterone and renin levels are low, while your cortisol level is high, you may have Cushing's syndrome.

Normal aldosterone levels

The aldosterone level in your blood is called plasma aldosterone concentration (PAC). A normal level depends on your age. On average, the normal PAC for adults can range from about 7 to 30 nanograms per deciliter (ng/dL), or from 3.1 to 35.4 ng/dL, depending on the lab and testing methods used.

Aldosterone levels can vary depending on many factors. In general, these are normal aldosterone levels by age: 

• Ages 1 to 12 months: 5.8-110.0 ng/dL
• Ages 1 to 5 years: Up to 36 ng/dL 
• Ages 6 to 9 years: Up to 24 ng/dL 
• Ages 10 to 11 years: Up to 15 ng/dL 
• Ages 12 to 14 years: Up to 22 ng/dL
• Ages 15 to 17 years: 3 to 32 ng/dL
• Ages 18 to 99 years: 3.1 to 35.4 ng/dL or 7 to 30 ng/dL

Factors That Affect Your Aldosterone Test Results

Many factors can influence your aldosterone levels. The time of day, your hormone levels, and whether you're pregnant can all affect your test results. 

Your doctor may ask you to follow certain instructions before your test. They could recommend repeating the test if they think that something has affected your results. 

Here are some factors that can affect aldosterone test results:

Food

Sodium and potassium can affect levels of hormones, including aldosterone. Your doctor may recommend changes to your diet for two weeks before your test, such as avoiding very salty foods and natural black licorice. You may also need to be careful about how much potassium you consume.

Time of day

Aldosterone levels are highest in the morning. The best time for a blood test to measure aldosterone levels is at least two hours after getting up.

Physical activity

Aldosterone levels can change because of your body position and physical activity. It's recommended to sit for 15 minutes before having your blood drawn. Standing up or lying down during the test may also affect your results.

Menstrual cycle 

Your menstrual cycle can affect aldosterone levels. Levels rise during the luteal phase (between when you ovulate and when your period starts). If you're premenopausal, your doctor may advise testing your aldosterone during the follicular phase (after your period ends and before ovulation begins).

Pregnancy

Renin is an enzyme made by your kidneys. It controls how aldosterone is produced. During pregnancy, renin levels increase more than aldosterone levels. This can throw off your test results. Your doctor will take this into consideration if you're tested while pregnant.

Stress

Feeling stressed can affect your aldosterone levels. Stress can trigger the release of renin, which leads to aldosterone production.

Medicines

Aldosterone tests can be affected by medications. You may need to stop taking certain prescription or nonprescription drugs for a certain period before your blood test. Some medicines that can change aldosterone test results include:

• Hormones (estrogens and progesterone)
• Corticosteroids
• High blood pressure medicines
• Heart medicines, such as beta-blockers
• Antacids and ulcer medicines
• Nonsteroid anti-inflammatory drugs 
• Diuretics

Risks of Aldosterone Testing

Any blood test comes with minor risks. You may have slight pain or a small bruise where the needle is inserted to draw blood. Most symptoms go away within a few days.

Takeaways

Aldosterone is a hormone that helps keep your blood pressure under control. An aldosterone test may be needed if you're having trouble managing your blood pressure. Conn's syndrome and Addison's disease can also affect aldosterone. When your aldosterone level is out of whack, it can lead to heart and kidney damage. A routine blood test can measure aldosterone levels and help your doctor figure out what’s going on.

Aldosterone FAQs

What does aldosterone do?

Aldosterone signals your organs, such as your colon and kidneys, to put more sodium into your bloodstream or release more potassium into your pee. This helps balance sodium and potassium levels in your body and keep your blood pressure in check.

Is aldosterone a vasoconstrictor?

A vasoconstrictor is something that causes your blood vessels to tighten, shrinking the space inside them. Aldosterone is a vasoconstrictor.

Does aldosterone increase blood pressure?

When aldosterone levels increase, it can cause your blood pressure to rise.

What is renin angiotensin aldosterone?

The renin-angiotensin-aldosterone system (RAAS) in your body helps control your blood pressure and blood volume. It includes renin (an enzyme), and the hormones angiotensin II and aldosterone. Enzymes trigger chemical reactions and can build or break down substances in your body. Hormones carry messages throughout your body to control different functions.

What does fludrocortisone do to aldosterone levels?

Fludrocortisone is a type of medicine called a corticosteroid. It is used to treat conditions such as Addison's disease, which is caused by a lack of aldosterone. Fludrocortisone does what aldosterone usually does in the body.