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24-Hour Urinary Free Cortisol Mass Concentration

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

This test measures the amount of cortisol, a natural steroid hormone, excreted in your urine over a 24-hour period. It helps assess how well your body produces and balances cortisol levels, which are important for stress response and other bodily functions.

Quick summary

["Helps diagnose adrenal gland issues or cortisol imbalance linked to stress or other conditions."]

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

Key facts at a glance

LOINC
68931-5
Short code
FCA 24h Ur-mCnc
Synonyms
FCA 24h Ur-mCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if they suspect conditions like Cushing’s syndrome (overproduction of cortisol), adrenal insufficiency, or other hormonal imbalances. It’s also used to monitor treatment effectiveness for conditions affecting cortisol levels.

How the Test Works

You’ll collect all urine for a full 24-hour period in a special container. The sample is then sent to a lab for analysis using a high-performance liquid chromatography (HPLC) method to measure cortisol concentration.

What to Expect Before the Test

No special preparation is needed, but you may be asked to drink extra fluids to ensure full collection. Avoid certain medications (like some steroids) that could affect cortisol levels unless instructed otherwise.

What the Results Mean

Results are compared to a reference range for healthy adults, but exact values can vary by lab. High levels may indicate Cushing’s syndrome or other causes of excess cortisol, while low levels could signal adrenal problems or stress-related depletion.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

24h Urine Free Cortisol

Frequently asked questions

What does cortisol do in the body?
Cortisol is a hormone produced by your adrenal glands that helps regulate metabolism, immune response, and stress reactions. Chronic high or low levels can affect energy, mood, weight, and overall health.
Can diet or lifestyle affect this test?
Yes—stressful events, certain medications, caffeine, or alcohol can influence cortisol levels. Your doctor may ask you to avoid these factors during your 24-hour urine collection.
Is this test painful or uncomfortable?
No, there’s no discomfort. You’ll just need to collect urine in a container for a full day, similar to how you’d collect a regular urine sample.
  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