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Plasma Renin Activity (PRA)

Published: August 9, 2026Updated: August 17, 2026

This test measures the activity of renin, an enzyme produced by your kidneys that helps regulate blood pressure and fluid balance.

Quick summary

["Renin helps control how much fluid stays in your body and how much pressure your blood exerts."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
2915-7
Short code
Renin Plas-cCnc
Synonyms
Renin Plas-cCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Ref low
0
Ref high
2
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

Why It’s Done

Your doctor may order this test if you have symptoms like high blood pressure, kidney problems, or conditions affecting fluid balance. It can also help diagnose certain hormonal or kidney disorders.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid certain medications or foods for a few days before testing. Your doctor will explain any restrictions.

During the Test

A blood sample is drawn from a vein, usually in your arm. The process is quick and typically painless, though you may feel a slight pinch.

After the Test

You can resume your normal activities immediately. There may be a small bruise or redness at the site, but this usually fades quickly.

Reference range

NCBI: SCC <2.0 ng/mLN/A

Specimen: plasma

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

High renin levels may indicate conditions like primary hyperaldosteronism or kidney disease, while low levels could suggest conditions like heart failure or certain hormonal imbalances. Results help guide treatment for blood pressure or fluid retention.

Short name

Renin Level

Frequently asked questions

What does a high renin level mean?
A high renin level might suggest your kidneys are trying to control blood pressure or fluid balance abnormally, possibly due to kidney disease, certain hormonal disorders, or conditions like pheochromocytoma.
What does a low renin level mean?
Low renin levels may indicate conditions like heart failure, liver disease, or certain medications that affect fluid balance. It can also be seen in people with normal kidney function but low blood pressure.
Does diet affect this test?
Yes, some foods and medications can influence renin levels. Your doctor may advise avoiding salt-heavy foods or certain medications (like diuretics) for a few days before testing to get more accurate results.
  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 17, 2026. · Read our editorial policy