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Aldosterone-to-Renin Ratio (ARR)

Published: August 9, 2026Updated: August 16, 2026

A blood test that compares aldosterone with renin activity to help screen for primary aldosteronism, a cause of high blood pressure.

Quick summary

["An elevated aldosterone-to-renin ratio may suggest primary aldosteronism."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
44124-6
Short code
MR Adrenal W contr IV
Synonyms
MR Adrenal W contr IV
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

The aldosterone-to-renin ratio, or ARR, is a blood test that compares the hormone aldosterone with renin activity. It is mainly used to help screen for primary aldosteronism.

Why might I need this test?

Your clinician may order this test if you have high blood pressure, especially if it is difficult to control or you have low potassium. It may also be used when hypertension or low potassium appears at an unexpectedly young age.

How is the test performed?

A blood sample is collected and the laboratory measures aldosterone and renin activity. The laboratory then calculates the aldosterone-to-renin ratio.

How do I prepare for the test?

Fasting is usually not required, but your clinician may give specific instructions. Many blood-pressure medicines, including some diuretics, can affect the results, so tell your clinician about all medications and supplements and do not stop prescribed medicines on your own.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated ratio may be associated with primary aldosteronism, in which the adrenal glands produce too much aldosterone. A low ratio can occur for other reasons, including low renin, and does not by itself confirm a diagnosis. Results must be interpreted with your blood pressure, potassium level, medications, and other laboratory findings; confirmatory testing may be needed.

Short name

Aldosterone-to-renin ratio

Frequently asked questions

Does an elevated aldosterone-to-renin ratio diagnose primary aldosteronism?
No. An elevated ratio suggests the condition but is not always diagnostic, and other factors can affect the result. Your clinician may recommend confirmatory testing.
Can medications affect this test?
Yes. Several blood-pressure medicines can alter aldosterone or renin levels. Keep taking prescribed medicines unless your healthcare professional instructs you otherwise.
Is fasting required for the aldosterone-to-renin ratio?
Fasting is generally not required, although the laboratory or your clinician may provide test-specific instructions. The test is commonly performed with the aldosterone and renin results interpreted together.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy