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24-Hour Free Cortisol (Urinary)

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

This test measures the amount of cortisol (a stress hormone) that appears in your urine over a 24-hour period, specifically the free (unbound) form.

Quick summary

["Helps assess how your body handles stress and adrenal function."]

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

Key facts at a glance

LOINC
14043-4
Short code
Cortis F 12h Ur-mRate
Synonyms
Cortis F 12h Ur-mRate
Category
hormone
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 a 24-hour free cortisol test to check for conditions like Cushing’s syndrome (overactive adrenal glands producing too much cortisol) or adrenal insufficiency (underactive adrenal glands). It can also help diagnose other hormonal imbalances or evaluate long-term cortisol exposure, such as from chronic stress or certain medications.

How the Test Works

You’ll collect all your urine for a full 24 hours, typically starting and ending at the same time each day. The urine is stored in a special container, and the sample is sent to the lab for analysis. The test measures cortisol levels in your urine to reflect your body’s natural cortisol production over time.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid certain medications or supplements that could affect cortisol levels. Follow your doctor’s instructions carefully to ensure accurate results.

What to Expect During the Test

You’ll collect urine in a container every time you urinate, including during sleep. The container may have a preservative to keep the sample stable. The test involves filling out a log to track when each urine sample was collected.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

What does a high or low result mean?
A high result may signal overproduction of cortisol, which could be due to a tumor, medication use, or conditions like Cushing’s syndrome. A low result may indicate adrenal insufficiency or other hormonal imbalances. Your doctor will interpret results in the context of your symptoms and other tests.
How often is this test repeated?
Your doctor may repeat this test if initial results are unclear or if you have ongoing symptoms. Additional tests, such as blood cortisol levels or imaging, may also be needed for diagnosis.
Can I take medications before the test?
Yes, but some medications (like steroids or certain antidepressants) can affect cortisol levels. Always inform your doctor or lab technician about all medications or supplements you’re taking 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