Learn more about aldosterone and renin, two hormones involved in blood pressure regulation.
The Aldosterone-Renin Ratio (ARR) Test measures aldosterone, plasma renin activity (PRA), and the ratio between these two markers. Together, these results provide insight into the body's hormone system that helps regulate blood pressure, fluid balance, and electrolyte levels.
Aldosterone is a hormone produced by the adrenal glands that helps control sodium, potassium, and fluid balance. Renin is an enzyme released by the kidneys that helps regulate aldosterone production. When aldosterone levels are elevated relative to renin activity, the result may be consistent with a pattern seen in primary aldosteronism (also known as hyperaldosteronism), a common and potentially treatable cause of high blood pressure. Primary aldosteronism can contribute to high blood pressure, low potassium levels, and increased cardiovascular risk. Test results can be influenced by certain medications, dietary salt intake, potassium levels, age, pregnancy, and underlying medical conditions.
Note: This test is not intended to diagnose, confirm, treat, or rule out any condition on its own. Your results should be reviewed by a healthcare professional who can interpret them along with your health history, medications, symptoms, blood pressure readings, and other lab results.
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Preparation: Sample should be collected mid-morning, after you have been up (sitting, standing, or walking) for at least two hours and seated for 5 to 15 minutes.
Maintain your usual salt intake before testing. Certain medications, including blood pressure medicines, diuretics, and products containing licorice root may affect results. Do not stop prescribed medications unless directed by your healthcare provider. If you take medications for high blood pressure, discuss test preparation with your provider before your appointment.
Aldosterone is a hormone produced by the adrenal glands (small glands that sit on top of your kidneys). It helps your body control blood pressure and maintain the balance of salt and potassium levels. Elevated aldosterone levels can cause the body to retain sodium and water while losing potassium, which may contribute to high blood pressure.
Renin is an enzyme produced by the kidneys that helps regulate blood pressure and fluid balance by controlling aldosterone production. Measuring plasma renin activity helps provide a more complete picture of how this hormone system is functioning.
The aldosterone-renin ratio (ARR) compares aldosterone with plasma renin activity to provide information about how this hormone system is functioning. Healthcare providers look at both the ratio and the individual aldosterone and renin results when interpreting the test. A pattern of lower renin levels together with higher-than-expected aldosterone levels may be associated with primary aldosteronism, a condition in which the adrenal glands produce too much aldosterone. Because many factors can affect these results, the ARR is used as a screening tool and does not diagnose a condition on its own.
High blood pressure can have many causes. This test measures aldosterone and renin, two hormones involved in blood pressure regulation. Results may provide information that helps support discussions with your healthcare provider about whether additional evaluation is appropriate.
Testing aldosterone and renin together may help you better understand how this important system is functioning.
Results may provide additional context that your healthcare provider can interpret alongside electrolyte levels, blood pressure history, medications, and other clinical information.
1. Young WF. Primary aldosteronism: renaissance of a syndrome. Clin Endocrinol (Oxf). 2007;66(5):607-618. doi:10.1111/j.1365-2265.2007.02775.x
2. Vaidya A, Carey RM. Evolution of the Aldosterone Concept: From Physiology to Clinical Practice. Endocr Rev. 2020;41(3):bnaa003.
3. National Heart, Lung, and Blood Institute. How the Body Regulates Blood Pressure. Accessed 2026.
4. MedlinePlus. Aldosterone Blood Test. U.S. National Library of Medicine. Updated 2024.
5. Endocrine Society. Primary aldosteronism. Published July 14, 2025. Accessed July 28, 2026. https://www.endocrine.org/clinical-practice-guidelines/primary-aldosteronism-2
<p>1. Young WF. Primary aldosteronism: renaissance of a syndrome. <i>Clin Endocrinol (Oxf)</i>. 2007;66(5):607-618. doi:10.1111/j.1365-2265.2007.02775.x</p> <p>2. Vaidya A, Carey RM. Evolution of the Aldosterone Concept: From Physiology to Clinical Practice. Endocr Rev. 2020;41(3):bnaa003.</p> <p>3. National Heart, Lung, and Blood Institute. How the Body Regulates Blood Pressure. Accessed 2026.</p> <p>4. MedlinePlus. Aldosterone Blood Test. U.S. National Library of Medicine. Updated 2024.</p> <p>5. Endocrine Society. Primary aldosteronism. Published July 14, 2025. Accessed July 28, 2026. <a rel="noopener noreferrer" href="https://www.endocrine.org/clinical-practice-guidelines/primary-aldosteronism-2" target="_blank" title="primary-aldosteronism">https://www.endocrine.org/clinical-practice-guidelines/primary-aldosteronism-2</a></p>
Simply purchase this test online. A healthcare provider will review and approve your test requests; no healthcare provider visit is required.
Visit a Labcorp location near you for sample collection. Visits may be scheduled online.
View your easy-to-read results online in your Labcorp Patient™ account, including Linked Accounts. For certain results that require prompt attention, you will also be contacted by phone or mail.
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Aldosterone is a hormone produced by the adrenal glands that helps regulate:
It works by signaling the kidneys to retain sodium and water while removing potassium, helping maintain healthy blood pressure and electrolyte balance.
A high ARR may indicate primary aldosteronism, a condition in which the adrenal glands produce too much aldosterone. Excess aldosterone can cause the body to retain sodium and lose potassium, which may contribute to high blood pressure that can be difficult to control.
It is important to understand that both conditions suppressed renin levels and an elevated ratio generally need to be present for the screen to be considered positive. A high ratio alone, especially when caused by very low renin and aldosterone levels, does not necessarily mean you have primary aldosteronism.
A positive ARR result does not mean you definitely have primary aldosteronism. It means the test has flagged a possible problem that may need further evaluation with your healthcare provider.
An aldosterone-renin ratio test may be appropriate for individuals who have:
This test may help identify whether excess aldosterone production may be contributing to high blood pressure and guide conversations with your healthcare provider about next steps. Speak with your healthcare provider about whether this test is appropriate for your situation.
Yes. PA is a common cause of secondary hypertension. Excess aldosterone can cause the body to retain sodium and water, which may raise blood pressure and increase cardiovascular risk over time, such as stroke, heart attack, and kidney disease. The good news is that identifying and treating PA can reduce these risks.
Many people with PA have no symptoms other than high blood pressure. When symptoms do occur, they may include:
It is important to know that most people with PA have normal potassium levels, so the absence of low potassium does not rule out this condition.
Fasting is typically not required for an ARR test; however, blood collection is typically recommended in the morning after you have been upright for at least two hours and seated for several minutes before the sample is collected. Certain medications, supplements, and dietary factors can affect aldosterone and renin levels. It's important to follow any preparation instructions provided by your healthcare provider. Do not stop taking prescribed medications unless instructed to do so by your provider.
The aldosterone:renin ratio (ARR) measures two hormones that help regulate blood pressure, fluid balance, and electrolytes. Many factors can affect these hormone levels, including certain medications (certain high blood pressure medications, NSAIDs, hormone therapy), salt intake, potassium levels, age, pregnancy, and some medical conditions. Because of this, test results may not always reflect your body's usual hormone activity.
For the most accurate results, it's important to follow the test preparation instructions and let your healthcare provider know about any medications or supplements you take. Do not stop taking prescribed medications unless directed by your healthcare provider. Your results should be interpreted alongside your medical history, blood pressure readings, and other clinical information.
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