Aaron Graves, PhDude (Replica)

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aldosterone renin ratio calculator

Posted on February 16, 2026 by Admin

ARR Screening Calculator

Estimate the aldosterone-to-renin ratio (ARR) for screening discussions around primary aldosteronism.

Default for PRA is often around 20–30, depending on lab protocol.

Please enter valid positive numbers for both aldosterone and renin.
Important: ARR is a screening tool, not a stand-alone diagnosis. Interpretation depends on medications, posture, sodium intake, potassium status, collection timing, and local assay methods.

What is the aldosterone-renin ratio (ARR)?

The aldosterone-renin ratio compares circulating aldosterone to renin. It is commonly used as an initial screen for primary aldosteronism (also called Conn syndrome), a potentially treatable cause of hypertension. A higher-than-expected ratio may suggest autonomous aldosterone production and can prompt confirmatory testing.

How to use this calculator

  • Enter aldosterone and choose its unit (ng/dL or pmol/L).
  • Enter renin and choose the assay type (PRA or DRC).
  • Use the default threshold or enter your clinic/lab-specific cutoff.
  • Click Calculate ARR to view ratio and a quick interpretation.

Default threshold guidance in this tool

Renin type Default threshold used Common practice note
PRA (ng/mL/h) 20 Many protocols use ~20 to 30 (with minimum aldosterone criteria).
DRC (mU/L) 2.4 Cutoffs vary by assay and local validation; often lower numeric values than PRA-based ARR.

How to interpret the result

ARR interpretation is not binary in all settings. A result can be affected by laboratory methods and patient preparation. Clinicians often combine:

  • ARR above assay-specific threshold,
  • Aldosterone above a minimum level (often around 10 ng/dL, protocol dependent),
  • Clinical context (hypertension pattern, hypokalemia, family history, adrenal imaging, and follow-up tests).

Pre-test factors that can change ARR

Medications

Mineralocorticoid receptor antagonists, diuretics, ACE inhibitors, ARBs, beta-blockers, and other antihypertensives can alter aldosterone, renin, or both. Test preparation should be guided by a clinician.

Physiology and sampling conditions

  • Posture (supine vs seated vs upright) before blood draw
  • Time of day and fasting status
  • Sodium intake
  • Potassium level (hypokalemia can suppress aldosterone)
  • Kidney function and volume status

When to discuss ARR with your clinician

  • Hypertension that is resistant to treatment
  • Hypertension with low potassium
  • Early-onset hypertension or strong family history
  • Adrenal incidentaloma with elevated blood pressure

Bottom line

This aldosterone renin ratio calculator provides a quick, transparent ARR estimate. It can support education and clinical conversations, but it does not replace lab-specific interpretation or formal endocrine workup.

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