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Aldosterone-to-Plasma Renin Activity Ratio, Plasma — Deprecated Test Name

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 and low potassium.

Quick summary

["An abnormal aldosterone-to-renin ratio may suggest primary aldosteronism and should be interpreted by your clinician."]

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

Key facts at a glance

LOINC
24886-4
Short code
Deprecated PAA XRA
Synonyms
Deprecated PAA XRA
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-fluor-angio
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?

This test measures aldosterone and renin activity in a blood sample and calculates their ratio. It is commonly used as a screening test for primary aldosteronism.

Why might I need this test?

It may be ordered for people with high blood pressure, especially if the blood pressure is difficult to control, potassium is low, or adrenal nodules are present.

How is the test performed?

A blood sample is collected and tested in a laboratory. The laboratory measures aldosterone and plasma renin activity and uses the results to calculate a ratio.

How do I prepare for the test?

Follow the laboratory's instructions about timing, posture, salt intake, and medication use. Some centers request testing while awake and upright or seated. Do not stop blood pressure medicines without medical advice, because several can affect the results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A raised aldosterone-to-renin ratio can occur with primary aldosteronism, in which the adrenal glands produce too much aldosterone. Low renin, kidney disease, age, very low sodium intake, and certain medicines can also alter the ratio, so an abnormal screening result does not confirm the diagnosis. Your clinician may repeat the test or request additional evaluation.

Short name

Aldosterone-to-renin ratio (ARR)

Frequently asked questions

Does an abnormal result mean I definitely have primary aldosteronism?
No. An abnormal ratio suggests that further evaluation may be needed, but other conditions and medications can affect the results. Confirmatory testing is sometimes required.
Can I take my blood pressure medicines before the test?
Do not stop or change medicines on your own. Some blood pressure drugs affect renin and aldosterone, so the laboratory or clinician should tell you how to prepare safely.
What happens if my potassium level is low?
Low potassium can occur with primary aldosteronism and can also affect test interpretation. Your clinician may correct low potassium or repeat the test before confirming the findings.
  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