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Plasma Renin Activity (measured as angiotensin I generation rate)

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

This test measures how much of the enzyme renin your blood produces, which helps regulate blood pressure and fluid balance.

Quick summary

["Renin activity helps assess kidney function and blood pressure regulation."]

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

Key facts at a glance

LOINC
100829-1
Short code
Renin sp4 p chal Plas-mCnc
Synonyms
Renin sp4 p chal Plas-mCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Ref low
44
Ref high
147
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84075
SNOMED
27550007
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 Is This Test Done?

Your doctor may order this test if you have symptoms like high blood pressure, kidney problems, or conditions affecting fluid balance (e.g., heart failure, kidney disease). It can also help diagnose or monitor certain hormonal or kidney-related disorders.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The blood is processed to measure renin activity over time, often by tracking the production of angiotensin I, a precursor hormone.

Sample Collection and Preparation

The test requires fresh plasma, which is separated from blood cells shortly after drawing your sample. This prevents clotting and ensures accurate results.

What Are Common Results?

Results are typically reported as a rate (e.g., angiotensin I generation per unit time), though exact reference ranges vary by lab and clinical context.

Reference range

Adult: 44-147 U/LN/A

Specimen: plasma

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Renin Activity

Frequently asked questions

What does a high renin level mean?
A high renin level may suggest your kidneys are working harder to regulate blood pressure, possibly due to conditions like kidney disease, heart failure, or certain hormonal imbalances. Your doctor will discuss findings in the context of your symptoms and other test results.
What does a low renin level mean?
A low renin level might indicate conditions like primary aldosteronism (where another hormone overproduces), kidney disease, or certain medications that affect fluid balance. Your doctor will review your medical history and other tests to interpret results accurately.
How often is this test repeated?
Your doctor may repeat this test if you have ongoing symptoms, changes in treatment, or if initial results suggest an underlying condition that needs further evaluation. Follow-up timing depends on your specific situation and medical team’s recommendations.
  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