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Cortisol, Free, 24-Hour Urinary

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

This test measures the amount of free cortisol (the active form) you excrete in your urine over a full day. It helps assess how your body produces and regulates cortisol, a hormone involved in stress response and metabolism.

Quick summary

["Helps diagnose conditions linked to abnormal cortisol levels, such as Cushing’s syndrome or adrenal insufficiency."]

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

Key facts at a glance

LOINC
1423-3
Short code
Cortis 45M p 1 ug/kg CRH IV SerPl-mCnc
Synonyms
Cortis 45M p 1 ug/kg CRH IV 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
CPT
86701
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 Matters

Cortisol is a hormone produced by your adrenal glands, which sit on top of your kidneys. It plays a key role in managing stress, immune response, and metabolism. Free cortisol in urine reflects your body’s natural cortisol production over time, without interference from other substances in the blood.

How the Test Works

You’ll collect all your urine for a full 24-hour period. The sample is then analyzed to measure the total cortisol excreted, which helps doctors evaluate whether your cortisol levels are too high or too low.

What to Expect Before the Test

No special preparation is needed, but you’ll need to collect every drop of urine for 24 hours, including at night. Drink plenty of fluids to help your kidneys pass urine consistently. Avoid taking any medications that might affect cortisol levels without discussing it with your doctor.

Possible Results and Interpretation

Results are compared to standard ranges for healthy adults. High levels may suggest conditions like Cushing’s syndrome, while low levels might indicate adrenal gland problems or other hormonal imbalances. Your doctor will discuss these findings with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Free Cortisol (Urine, 24 hr)

Frequently asked questions

Why would my doctor order this test?
Your doctor may recommend this test if you have symptoms like unexplained weight gain, fatigue, high blood pressure, or changes in your mood or sleep patterns. It’s also used to diagnose or monitor conditions like Cushing’s syndrome, adrenal insufficiency, or to check for cortisol-secreting tumors.
What if my results are out of the normal range?
If your results are abnormal, your doctor will review them with you and may order additional tests or evaluations. This could include further blood tests, imaging studies, or other specialized assessments to determine the cause and guide treatment.
Can I take medications before this test?
Some medications, like certain steroids or blood pressure drugs, can affect cortisol levels. Always inform your doctor or lab technician about all medications, supplements, or herbal products 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