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Serum or Plasma Free Aldosterone Concentration (24-Hour Urine Aldosterone Excretion)

Published: August 9, 2026Updated: August 17, 2026

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

Quick summary

["Helps diagnose conditions affecting hormone levels and blood pressure regulation."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
68901-8
Short code
RBC Dial fld Ql
Synonyms
RBC Dial fld Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
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, unusual thirst, or signs of hormone imbalances. It’s also used to check for conditions like primary aldosteroneism (Conn’s syndrome) or adrenal gland issues.

What to Expect Before the Test

You’ll collect all your urine for 24 hours, starting right after midnight of one day and ending right after midnight the next. Drink plenty of water but avoid foods that might affect aldosterone levels (like salt).

How the Test Works

The collected urine is sent to a lab to measure aldosterone levels. The test helps determine if your body is producing too much or too little aldosterone.

Possible Results and Interpretation

Results are compared to standard ranges, but exact values depend on lab methods. High levels may suggest conditions like primary aldosteroneism, while low levels could indicate adrenal insufficiency or other hormonal disorders.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

24-Hour Aldosterone Urine Test

Frequently asked questions

What does high aldosterone urine levels mean?
High aldosterone in urine may indicate primary aldosteroneism (Conn’s syndrome), where your adrenal glands overproduce aldosterone, leading to high blood pressure and fluid retention. It can also be seen in certain kidney or liver diseases.
What does low aldosterone urine levels mean?
Low aldosterone levels in urine may suggest adrenal gland problems (like Addison’s disease), where the body doesn’t produce enough aldosterone, or conditions affecting hormone regulation.
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. Follow-up may be needed if your blood pressure or hormone levels are abnormal.
  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 17, 2026. · Read our editorial policy