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24-Hour Urinary Free Cortisol (Mass Concentration)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of cortisol, a natural steroid hormone, excreted in your urine over a full day. It helps assess how well your body produces and regulates cortisol, which plays a key role in managing stress, immune response, and metabolism.

Quick summary

["This test helps diagnose conditions related to cortisol imbalance, such as Cushing’s syndrome or adrenal insufficiency."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
26525-6
Short code
Cortis F 24h p ACTH 24h Ur-mCnc
Synonyms
Cortis F 24h p ACTH 24h Ur-mCnc
Category
hormone
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
10
Ref high
60
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 an issue with your adrenal glands or pituitary gland, which control cortisol production. It’s also used to monitor conditions like Cushing’s syndrome or adrenal insufficiency, where cortisol levels are either too high or too low. Sometimes, it’s part of a broader evaluation for unexplained weight changes, fatigue, or other symptoms linked to hormone imbalances.

What to Expect Before the Test

You’ll need to collect all urine for a full 24-hour period, typically starting and ending at the same time each day. A healthcare provider will give you instructions on how to properly collect your urine samples. It’s important to drink enough fluids to ensure your urine output is normal throughout the day.

What Happens During the Test

After collecting your urine samples, they will be sent to a lab for analysis. The lab will measure the amount of cortisol in your urine, which is then compared to standard reference ranges to determine if your levels are within normal limits or if further evaluation is needed.

What the Results Mean

Results can show whether your cortisol levels are consistently too high or too low over 24 hours. Elevated levels might indicate conditions like Cushing’s syndrome, while lower levels could suggest adrenal insufficiency or other hormonal issues. Your doctor will interpret the results in the context of your symptoms and medical history.

Reference range

NCBI: ACTH 10-60 pg/mLN/A

Specimen: urine

Typically collected in the morning (8-10 AM). Inform your provider if taking steroid medications.

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 a high cortisol level in urine mean?
High urinary cortisol levels over 24 hours may suggest Cushing’s syndrome, where the body produces too much cortisol. This can cause symptoms like weight gain, high blood pressure, muscle weakness, and mood changes. It’s important to discuss these findings with your doctor to determine the next steps, which may include further testing or treatment.
What does a low cortisol level in urine mean?
Low urinary cortisol levels can indicate adrenal insufficiency, where the adrenal glands don’t produce enough cortisol. This might lead to fatigue, low blood pressure, weight loss, and salt cravings. Your doctor will work with you to understand the cause and explore appropriate treatment options.
Why might my doctor order this test?
Your doctor might order this test if you have symptoms like unexplained weight changes, frequent infections, fatigue, or unusual mood swings. It can also be part of a diagnostic workup for suspected hormonal disorders or to monitor conditions like Cushing’s syndrome or adrenal gland issues.
  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 17, 2026. · Read our editorial policy