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Serum or plasma concentration of renin (active form)

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

This test measures the active form of the enzyme renin, which plays a key role in regulating blood pressure and fluid balance in your body.

Quick summary

["Renin helps control how much fluid stays in your bloodstream and affects your blood pressure levels."]

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

Key facts at a glance

LOINC
37960-2
Short code
XR Ribs.lower-R Views
Synonyms
XR Ribs.lower-R Views
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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 your body’s fluid balance. It can also help diagnose or monitor certain kidney-related disorders or conditions like primary aldosteronism or renovascular hypertension.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the test if it’s part of a broader blood panel. Bring any medications you’re currently taking to your appointment.

What Happens During the Test?

A healthcare professional will draw blood from a vein, typically in your arm. The blood sample is sent to a lab for analysis to measure the active renin concentration.

What Are the Results?

Results are interpreted by your doctor based on your overall health, symptoms, and medical history. Elevated levels may suggest conditions like primary aldosteronism or certain kidney diseases, while lower levels might indicate conditions affecting renin production.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Active Renin Level

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend this test if you have symptoms like unexplained high blood pressure, kidney problems, or if they suspect conditions like primary aldosteronism, renovascular hypertension, or certain types of heart disease. It can also help monitor kidney function or fluid balance in some cases.
What does a high or low renin level mean?
A high renin level might suggest conditions like primary aldosteronism, where your adrenal glands produce too much aldosterone, or certain kidney diseases. A low renin level could indicate conditions affecting renin production, such as heart failure, liver disease, or certain hormonal imbalances. Your doctor will discuss these findings with you.
Do I need to prepare for this test?
Generally, no special preparation is needed, but follow any specific instructions your doctor provides. If you’re on medications, bring a list to your appointment 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