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Plasma renin activity (PRA) with angiotensin I generation measurement

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

This test measures how your kidneys produce a hormone called renin, 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
73170-3
Short code
Ramipril ind plt IgM SerPl Ql FC
Synonyms
Ramipril ind plt IgM SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
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 to evaluate kidney function, check for conditions like hypertension (high blood pressure), or monitor the effects of medications that affect the renin-angiotensin system, such as ACE inhibitors.

What Does the Test Measure?

The test measures renin levels in your plasma and indirectly assesses how much angiotensin I (a precursor hormone) is generated from angiotensinogen in your blood.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is processed to measure renin activity and angiotensin I generation, often using an immunoassay or similar method.

What Are Common Reasons for Testing?

It may be used to diagnose or monitor conditions such as primary hyperaldosteronism, renal artery stenosis, or to assess responses to medications like ACE inhibitors.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test helps identify imbalances in the renin-angiotensin system, which can indicate kidney disease, uncontrolled hypertension, or other endocrine disorders. Elevated or low renin levels may signal specific health concerns that require further evaluation.

Frequently asked questions

What does a high or low renin level mean?
A high renin level may suggest conditions like kidney disease, low blood volume, or certain types of hypertension. A low renin level could indicate conditions like primary aldosteronism or excessive use of certain medications.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time.
Can I eat or drink anything before this test?
No special preparation is usually needed, but follow your doctor’s instructions if they specify any restrictions, such as fasting for other tests.
  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