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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. Renin plays a key role in regulating your 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
12903-1
Short code
Renin sp5 p chal Plas-cCnc
Synonyms
Renin sp5 p chal Plas-cCnc
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 This Test Might Be Ordered

Your doctor may order this test if they suspect you have conditions like high blood pressure (hypertension), kidney disease, or aldosteroneism. It can also help evaluate whether your kidneys are properly controlling fluid and salt balance, especially if you have symptoms like swelling, frequent urination, or fatigue.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications (like blood pressure drugs) for a few days before testing. Your blood will be drawn from a vein in your arm, similar to other blood tests.

How the Test Works

A small sample of your blood is taken and sent to a lab. There, it’s analyzed to measure how much angiotensin I (a hormone) is produced from renin over a set period. This process helps determine your renin activity level.

What the Results Mean

Results are typically reported as a rate (e.g., amount of angiotensin I generated per unit of time). High or low levels may indicate underlying health issues that need further evaluation by your doctor.

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 indicate conditions affecting your kidneys or adrenal glands, such as certain types of kidney disease or hormonal imbalances. Your doctor will discuss these findings with you and may recommend further tests or adjustments to your treatment plan.
What does a low renin level mean?
A low renin level may suggest conditions like heart failure, liver disease, or certain medications that affect fluid balance. It’s important to talk with your doctor to understand why this result occurred and what steps might be needed next.
Can diet or medications affect this test?
Yes, certain medications (like blood pressure drugs) and dietary changes (such as salt restriction) can influence renin levels. Your doctor will provide specific instructions if this test is part of your care plan.
  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