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Plasma Renin Activity (PRA) – 24-Hour Urinary

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

This test measures how much renin your kidneys release over 24 hours, collected in your urine. Renin is an enzyme that plays a key role in regulating your blood pressure and fluid balance.

Quick summary

["Assesses kidney function and blood pressure regulation through urinary renin levels over a full day."]

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

Key facts at a glance

LOINC
48786-8
Short code
Renin 30M pre chal Plas-cCnc
Synonyms
Renin 30M pre 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 Is Done

Your doctor may order this test if you have symptoms like high blood pressure, kidney problems, or signs of fluid imbalance. It helps evaluate whether your kidneys are producing enough renin or if there’s an imbalance in your body’s natural blood pressure system.

What to Expect Before the Test

You’ll collect your urine for 24 hours, starting after midnight of one day and ending just after midnight the next. Store the urine in a refrigerator until you return it to the lab. Avoid certain medications that might affect results, as directed by your doctor.

What the Test Results Mean

Higher-than-normal levels may suggest conditions like kidney disease, certain hormonal imbalances, or excessive fluid loss. Lower-than-normal levels could indicate conditions affecting kidney function or blood pressure control. Your doctor will interpret results in the context of your overall health.

Common Conditions Linked to Renin Activity

Abnormal renin levels can be linked to conditions like primary hyperaldosteronism (high blood pressure due to overactive adrenal glands), chronic kidney disease, or conditions causing fluid retention or loss.

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

24-Hour Urinary Renin Activity

Frequently asked questions

What causes false high or low renin levels in this test?
False high levels may occur if you’re dehydrated, taking certain medications (like diuretics), or have kidney disease. False low levels can happen if you’re overhydrated, have liver disease, or are taking medications that affect fluid balance. Always discuss your medications and health history with your doctor before the test.
How often should I get this test?
Your doctor will determine how often you need this test based on your symptoms, medical history, and other test results. It’s usually not a routine test unless you have specific concerns about blood pressure or kidney function.
Can I eat or drink anything special before this test?
No special diet or restrictions are needed for this test. Drink as usual unless your doctor advises otherwise. Avoid alcohol or caffeine in excess, as they may affect urine collection.
  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