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Cortisol, 24-hour urinary free cortisol

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

This test measures how much cortisol your body naturally produces and excretes over a full day through your urine.

Quick summary

["Assesses long-term cortisol levels to help diagnose conditions like Cushing’s syndrome or adrenal gland issues."]

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

Key facts at a glance

LOINC
55845-2
Short code
Cortis F 24h Ur RIA-mCnc
Synonyms
Cortis F 24h Ur RIA-mCnc
Category
hormone
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ria
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 hormonal imbalances, such as overproduction of cortisol (Cushing’s syndrome) or adrenal insufficiency. It helps track daily cortisol levels that can’t be measured in blood alone.

How the Test Works

You’ll collect all your urine for a 24-hour period (typically from one morning to the next). The sample is then analyzed to measure cortisol concentration.

Sample Collection

Follow your healthcare provider’s instructions precisely—use a clean container, keep the sample refrigerated, and return it on time. Missing or improperly collected samples can affect results.

What to Expect

No special preparation is needed, but avoid certain medications (like steroids) that could alter cortisol levels. Stress or illness may also impact results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

24-Hour Urine Cortisol

Frequently asked questions

What Does It Mean?
High levels may indicate Cushing’s syndrome, adrenal tumors, or long-term steroid use. Low levels could signal adrenal gland problems, pituitary disorders, or stress-related cortisol drops.
FAQ: How Accurate Is This Test?
This test is reliable for detecting chronic cortisol overproduction but may not catch short-term spikes. Always discuss results with your doctor.
FAQ: Can I Take Medications Before Testing?
Avoid steroids or other cortisol-altering drugs unless cleared by your provider. Some over-the-counter supplements (e.g., licorice) may also affect results.
  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