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Serum or Plasma Free Aldosterone Concentration (Substance Concentration)

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

This test measures the amount of free (unbound) aldosterone in your blood, a hormone that helps regulate blood pressure and fluid balance.

Quick summary

["Aldosterone plays a key role in managing how much sodium and water your body retains, which can affect your blood pressure levels."]

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

Key facts at a glance

LOINC
63347-9
Short code
ENA SS-A Ab Fld Ql IA
Synonyms
ENA SS-A Ab Fld Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 It’s Ordered

Your doctor may order this test if you have symptoms like high blood pressure, low potassium levels, or signs of conditions like primary aldosteroneism (Conn’s syndrome). It may also be used to monitor certain hormonal disorders or before certain treatments.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications or dietary changes for 24 hours before testing. If you’re taking medications like potassium-sparing diuretics, your doctor may instruct you to stop them temporarily.

What the Test Involves

A blood sample is drawn from a vein, typically in your arm. The sample is then sent to a lab for analysis to measure free aldosterone levels.

What the Results Mean

Results are compared to a reference range provided by your healthcare provider. Elevated levels may suggest conditions like hyperaldosteronism, while lower levels could indicate other hormonal imbalances or medical conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Free Aldosterone

Frequently asked questions

What might cause abnormal results?
Abnormally high aldosterone levels can lead to high blood pressure, low potassium, and other health issues. Low levels may indicate conditions like adrenal insufficiency or certain medications affecting hormone balance.
How often should I get this test?
The frequency depends on your health condition and treatment plan. Your doctor will determine how often you need retesting based on your symptoms and lab results.
Can I eat or drink anything before the test?
Generally, you can eat and drink normally unless instructed otherwise. Some tests may require fasting, but this test does not typically require dietary restrictions.
  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