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Cortisol, 24-Hour Urinary Free

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

This test measures the amount of cortisol, a natural steroid hormone, excreted in your urine over a full day. It helps assess your body’s cortisol production and adrenal gland function.

Quick summary

["This test helps evaluate adrenal health and stress response over time."]

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

Key facts at a glance

LOINC
12557-5
Short code
Cortis sp2 p chal SerPl-mCnc
Synonyms
Cortis sp2 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 This Test Is Done

Your doctor may order a 24-hour urinary cortisol test if they suspect conditions like Cushing’s syndrome (overactive adrenal glands causing high cortisol) or adrenal insufficiency (low cortisol). It can also help diagnose other hormonal imbalances or stress-related issues.

What to Expect Before the Test

You’ll collect all urine from the moment you wake up until the next morning. Use a clean container each time, and discard the first urine of the day. Store the samples in a refrigerator until you return them to the lab.

What Happens During the Test

No special preparation is needed beyond collecting urine over 24 hours. The lab analyzes the combined sample to measure cortisol levels.

What the Results Mean

Results are compared to typical 24-hour urinary cortisol ranges. High levels may indicate overproduction of cortisol, while low levels may suggest adrenal problems or stress-related fatigue.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Cortisol’s Role in Health

Short name

24-Hour Urinary Cortisol

Frequently asked questions

What causes false high or low results?
False high results can occur if you’re taking certain medications (e.g., steroids), have recent illness, or didn’t follow collection instructions. False low results may happen if you missed any urine samples or had dehydration.
How often should I get this test?
Your doctor will determine the frequency based on your symptoms and medical history. It’s often done once or twice if needed for diagnosis.
Can I drink alcohol before this test?
Yes, but avoid excessive alcohol, as it may affect cortisol levels. Stick to your usual diet and activity levels unless instructed otherwise.
  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