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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 blood pressure and fluid balance.

Quick summary

["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
56758-6
Short code
Renin 70M p chal Plas-cCnc
Synonyms
Renin 70M 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 Is This Test Done?

Your doctor may order this test if they suspect you have conditions affecting your kidneys, blood pressure, or fluid balance, such as hypertension, kidney disease, or aldosterone-related disorders. It can also help diagnose or monitor certain hormonal imbalances or conditions like primary aldosteronism.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure renin activity over time. The process is similar to other blood tests and typically takes a few minutes.

What Should You Know Before the Test?

You may be asked to avoid certain medications or supplements that could affect the results, such as some blood pressure drugs or diuretics. Your doctor will provide specific instructions based on your health and the test requirements.

How Long Does It Take to Get Results?

Results are usually available within a few days to a week, depending on your lab’s processing time. Your doctor will discuss the results with you during your follow-up visit.

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 (plasma)

Frequently asked questions

What does a high or low renin level mean?
A high renin level might suggest conditions like kidney disease, low blood volume, or certain types of hypertension. A low renin level could indicate conditions such as primary aldosteronism, kidney damage, or excessive use of certain medications.
How do I prepare for this test?
Follow your doctor’s instructions carefully. Typically, you may need to avoid certain medications or fluids for a short period before the test. Some tests may require fasting, so check with your healthcare provider.
Can I take my usual medications before the test?
Your doctor will advise you on whether to take your usual medications as scheduled. Some medications may need to be temporarily adjusted or skipped to ensure 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 16, 2026. · Read our editorial policy