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Plasma Aldosterone Concentration (24-Hour Urine Aldosterone Excretion Rate)

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

This test measures how much aldosterone your body excretes in urine over 24 hours. Aldosterone is a hormone that helps regulate blood pressure and fluid balance.

Quick summary

["Helps diagnose conditions affecting your body’s sodium, potassium, or blood pressure regulation."]

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

Key facts at a glance

LOINC
57583-7
Short code
Aldost 2h p 25 mg Cpl PO SerPl-sCnc
Synonyms
Aldost 2h p 25 mg Cpl PO SerPl-sCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 they suspect conditions like primary aldosteroneism (Conn’s syndrome), adrenal gland tumors, or other disorders that affect hormone balance. It can also help evaluate kidney function or check for signs of high blood pressure linked to hormonal imbalances.

What to Expect Before the Test

You’ll likely collect a 24-hour urine sample starting from one morning and ending the next morning. Drink plenty of water but avoid foods high in potassium or salt if instructed. Follow any special instructions your doctor provides to ensure accurate results.

What Happens During the Test

No special preparation is needed beyond collecting urine in a container over the full 24-hour period. Bring all collected urine samples to your lab visit for testing.

What the Results Mean

High aldosterone levels may indicate overactive adrenal glands or other conditions affecting blood pressure or fluid balance. Low levels could suggest adrenal insufficiency or other hormonal issues. Your doctor will interpret results in relation to your symptoms and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Aldosterone (24-hour urine)

Frequently asked questions

How often should I collect urine for this test?
Collect urine starting from the first void of one morning and continue until the first void of the next morning. This ensures a full 24-hour sample. If you miss any urine, discard it and restart the collection.
Can I take medications before this test?
Some medications may affect aldosterone levels. Ask your doctor whether to stop any medications temporarily or if you need to adjust timing. Never stop taking prescribed medications without consulting your doctor first.
What if I have kidney problems?
Kidney function impacts urine aldosterone excretion. If you have kidney disease, your doctor may adjust the test or use alternative methods. Let your doctor know about any kidney issues before the test.
  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