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Aldosterone

A hormone from the adrenal glands that helps your kidneys hold on to salt and water and release potassium. It helps control blood pressure.

AI-drafted. Awaiting verificationAlso called ALDO, PACLOINC 1763-2

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What it is

Aldosterone is made in the outer layer of the adrenal glands. It tells the kidneys to keep sodium (salt) and water and to release potassium, which helps set your blood pressure. Renin, a hormone from the kidneys, usually pushes aldosterone up. A high-salt diet or lying down usually pushes it down. Because so many things move it, aldosterone is almost always read together with renin and your potassium level.

Why it matters

Too much aldosterone can raise blood pressure and lower potassium. When the adrenal glands make too much on their own, it is called primary aldosteronism, and experts think it often goes unrecognized as a cause of high blood pressure. The Endocrine Society's 2025 guideline suggests testing aldosterone and renin in everyone with high blood pressure. Too little aldosterone can lead to low sodium, high potassium and low blood pressure. A single aldosterone number is hard to judge without renin, posture, salt intake and medicines.

If it’s low

A low result is often explained by a high-salt diet, lying down before the draw, low potassium or common blood pressure medicines. Less often, the adrenal glands or the renin system aren't working as they should. A clinician reads it together with renin, sodium and potassium.

Common causes

  • A high-salt diet
  • Medicines that lower aldosterone, including ACE inhibitors, angiotensin receptor blockers, beta-blockers and clonidine
  • Low potassium
  • Older age
  • Lying down for a long time before the draw
  • Adrenal gland failure (Addison disease) or a problem with renin, which are uncommon

What can help

  • Tell your clinician about all medicines and supplements you take
  • Ask whether sodium and potassium should be checked
  • Ask whether the test should be repeated under standard conditions

If it’s high

A high result is read next to renin. If renin is low, the adrenal glands may be making more aldosterone than the body needs. If renin is high, the body is usually pushing aldosterone up in response to something else, such as low salt intake, fluid loss or a medicine, and that is common. Standing up, being active and some medicines also raise it.

Common causes

  • Standing, walking or sitting up before the draw, instead of lying down
  • Low salt intake, dehydration or fluid loss
  • Water pills (diuretics), aldosterone-blocking medicines, and estrogen-containing birth control or hormone therapy
  • Pregnancy
  • A high potassium level
  • Conditions that lower blood flow to the kidneys, such as narrowed kidney arteries, heart failure or advanced liver disease
  • Primary aldosteronism, where the adrenal glands make too much aldosterone on their own

What can help

  • Ask whether renin and potassium were checked at the same time
  • Ask whether your blood pressure medicines could have changed the result, and don't stop any on your own
  • Ask whether the draw was done seated, in the morning, on your usual salt intake

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–30 ng/dL. Source: Labcorp, ARUP Laboratories.

What can affect your result

  • Posture: higher when upright than when lying down
  • Salt intake: low salt raises aldosterone and high salt lowers it
  • Potassium level: low potassium can make aldosterone look falsely low
  • Medicines: ACE inhibitors, angiotensin receptor blockers, beta-blockers and clonidine lower it; diuretics, aldosterone-blocking medicines and estrogen raise it
  • Time of day, age and pregnancy
  • Method: LC-MS/MS reads lower than older immunoassays
  • Posture: levels are higher after standing or walking than after lying down.
  • Salt intake: low salt raises aldosterone and high salt lowers it. Ranges assume a normal salt diet, and guidelines advise against restricting salt in the days before testing.
  • Low potassium can make aldosterone look falsely low. Potassium is usually measured at the same time.
  • Medicines that lower aldosterone include ACE inhibitors, angiotensin receptor blockers, beta-blockers and clonidine. Water pills, aldosterone-blocking medicines, estrogen-containing birth control or hormone therapy, and drospirenone raise it. Never stop a blood pressure medicine on your own, because your clinician decides whether any change is needed before a test.
  • Pregnancy raises aldosterone.
  • Method: LC-MS/MS reads lower than older immunoassays, so cut points and ranges differ by method.

Morning, seated. The Endocrine Society (2025) suggests a morning draw with the person seated; Labcorp asks for a draw after being up and walking for at least 30 minutes, and ARUP asks for a seated draw in the morning without a long tourniquet time. Posture, salt and fluid shifts move it within hours to days. Medicines that affect the test can take weeks to clear; the Endocrine Society (2025) lists 2 to 4 weeks for the ones that interfere most.

When to talk to a clinician

Contact the clinician who ordered the test if your lab flagged the result, if your blood pressure stays high on treatment, or if you have a low potassium result. Seek urgent care for severe muscle weakness, fainting, a racing or uneven heartbeat or confusion. If you feel very unwell, call 911 or your local emergency number.

Questions you could ask

  • Given my blood pressure history, is testing aldosterone and renin worthwhile for me?
  • Was my renin measured at the same time, and what do the two results show together?
  • Could my medicines, salt intake or the way I was seated have affected this result?
  • Should we also check my potassium?
  • Could my medicines or salt intake explain this result?
  • Should we check my sodium and potassium?

Questions people ask

Why does it matter whether I was sitting or lying down?

Standing or sitting raises aldosterone and lying down lowers it. Some labs print a lying-down range and an upright range. Guidelines suggest a morning draw while seated. Tell the person drawing your blood if you were lying down beforehand.

Why is aldosterone usually ordered with renin?

The two hormones usually move together. When renin is low but aldosterone is not, the pair can be a sign that the adrenal glands are working on their own. That is why guidelines suggest measuring both and comparing them as a ratio.

How do I convert ng/dL to pmol/L?

Multiply ng/dL by 27.7, so 10 ng/dL is about 277 pmol/L. To get pg/mL, multiply ng/dL by 10.

Show the science and sources

Units

  • 1 ng/dL = 1 ng/dL
  • 1 ng/dL = 27.75 pmol/L
  • 1 ng/dL = 10 pg/mL
  • 1 ng/dL = 10 ng/L

Open the Aldosterone unit converter

Is a change real?

Aldosterone naturally varies about 48.8% from test to test in the same healthy person. Between two results from the same lab, a rise of 324% or more, or a fall of 76% or more, is unlikely to be day-to-day noise or lab variation (95% reference change value). Source: Biological Variation of Adrenal-Related Endocrine Biomarkers Used for Investigation of Secondary Hypertension (Lerpold AS et al.).

For clinicians and researchers

Aldosterone is the main mineralocorticoid, made in the zona glomerulosa and driven mainly by angiotensin II and potassium. Immunoassays (for example CLIA) and LC-MS/MS give different values, with LC-MS/MS reading lower, and the Endocrine Society's 2025 primary aldosteronism guideline uses a lower threshold for it. In that guideline a positive screen in most circumstances needs renin to be suppressed (plasma renin activity 1 ng/mL/h or less, or direct renin concentration 8.2 mU/L or less) and aldosterone of 10 ng/dL (277 pmol/L) or more by immunoassay, or 7.5 ng/dL (208 pmol/L) or more by LC-MS/MS. It asks for a morning, seated draw without prolonged venous stasis, no dietary sodium restriction in the days before, and potassium measured alongside, because low potassium can lower aldosterone. Beta-blockers can cause a false positive when aldosterone is under 15 ng/dL by immunoassay or under 10 ng/dL by LC-MS/MS. The guideline also says to rely on local cut points where possible. Labs print posture-specific ranges: ARUP, ages 15 and older, lists up to 31.0 ng/dL with posture unspecified, up to 16.0 supine and 4.0 to 31.0 upright, and notes these assume normal sodium intake. Conversion: ng/dL × 27.74 = pmol/L (molecular weight 360.4).

LOINC 1763-2 (primary), 14586-2, 1767-3, 1768-1, 92897-8. Specimen: serum-or-plasma.

Sources

  1. Aldosterone, LC/MS (test 004374), Labcorp
  2. Aldosterone, Serum (test 0070015), ARUP Laboratories
  3. Primary Aldosteronism: An Endocrine Society Clinical Practice Guideline, Journal of Clinical Endocrinology & Metabolism (2025)
  4. Aldosterone-Renin Ratio (Test Fact Sheet), ARUP Consult (2026)
  5. Aldosterone (PubChem CID 5839), NCBI PubChem

AI-drafted. Awaiting verification. Last reviewed 2026-10-03. How we build and check these pages.

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