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Cortisol, Free, Serum (24-hour urinary excretion)

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

This test measures the amount of free cortisol your body excretes in urine over a 24-hour period. Free cortisol is a form of cortisol that is not bound to proteins and can be detected in urine.

Quick summary

["Free cortisol in urine helps assess adrenal gland function and hormone balance."]

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

Key facts at a glance

LOINC
1448-0
Short code
Cortis pre 500 ug Dex SerPl-mCnc
Synonyms
Cortis pre 500 ug Dex 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 healthcare provider may order this test if you have symptoms like unexplained weight changes, fatigue, or signs of hormone imbalances. It could also be used to diagnose conditions such as Cushing’s syndrome (too much cortisol) or adrenal insufficiency (too little cortisol).

What to Expect Before the Test

You’ll need to collect all urine for a full 24-hour period, starting right after you wake up and ending just before you wake up the next day. Collect all urine in a container, keeping it refrigerated if possible. Avoid certain medications that can affect cortisol levels.

What the Test Results Mean

Results are compared to typical ranges for healthy individuals. High levels may indicate conditions like Cushing’s syndrome, while low levels could suggest adrenal problems or other hormonal disorders.

Common Conditions This Test Helps Diagnose

This test is particularly useful for diagnosing hormonal imbalances, such as whether your adrenal glands are producing too much or too little cortisol. It can also help confirm suspected Cushing’s syndrome or adrenal insufficiency.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Frequently asked questions

How long does it take to get my test results?
Results are typically available within 1 to 3 business days, depending on your lab. Follow up with your healthcare provider to discuss the findings.
Can I eat or drink anything before this test?
No special diet or fasting is required for this test. However, avoid caffeine and alcohol for 24 hours before collecting urine to avoid interference with results.
Will I need to take any special steps during the urine collection?
Yes, collect every drop of urine for the full 24-hour period. If you miss any urine, start over from the next morning’s collection. Keep the sample refrigerated and label it clearly with the start and end times.
  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