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Cortisol (24-hour urinary free cortisol)

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 regulates cortisol.

Quick summary

["Helps diagnose adrenal gland disorders and cortisol imbalance."]

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

Key facts at a glance

LOINC
12568-2
Short code
Cortis 20M p chal SerPl-mCnc
Synonyms
Cortis 20M p chal SerPl-mCnc
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is This Test Done?

Your doctor may order a 24-hour urine cortisol test if they suspect conditions like Cushing’s syndrome (overproduction of cortisol) or adrenal insufficiency (underproduction). It can also help evaluate cortisol levels in people with unexplained weight changes, high blood pressure, or other symptoms linked to hormonal imbalances.

How Is the Test Performed?

You’ll collect all urine for a full 24-hour period in a special container. Typically, you start the collection after waking up and finish just before going to bed the next day. The sample is then sent to a lab for analysis.

What Are Common Results?

Results are compared to standard ranges for healthy adults, but exact values can vary by lab. Abnormal results may signal hormonal issues requiring further evaluation.

What Are Possible Side Effects?

There are no direct side effects from collecting urine samples, but improper collection (e.g., missing early/late urine) can affect accuracy. Follow your doctor’s instructions carefully.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Cortisol is a key stress hormone produced by the adrenal glands. Elevated levels may indicate Cushing’s syndrome, while low levels could signal adrenal failure or other conditions. This test provides a comprehensive picture of daily cortisol exposure, unlike single blood tests.

Short name

24-Hour Urine Cortisol

Frequently asked questions

What does a high 24-hour urine cortisol mean?
A high result may suggest overactive adrenal glands or conditions like Cushing’s syndrome. Your doctor will review your symptoms and other test results to determine the cause.
How often is this test repeated?
If initial results are abnormal, your doctor may repeat the test or recommend additional tests (e.g., blood cortisol levels) to confirm the diagnosis.
Can diet affect this test?
Yes—avoid foods with high natural cortisol (e.g., chocolate, coffee) or supplements (e.g., licorice) for 24 hours before testing. Stress and exercise can also temporarily alter 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