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Cortisol (Serum) - 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, which plays a key role in managing stress, immune response, and metabolism.

Quick summary

This test helps diagnose conditions related 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
48100-2
Short code
Cortis 15M pre 1 ug/kg CRH IV SerPl-mCnc
Synonyms
Cortis 15M pre 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 Is Done

Your doctor may recommend this test if they suspect you have conditions like Cushing’s syndrome (too much cortisol) or adrenal gland problems (too little cortisol). It can also be used to monitor treatment for these conditions or to check for hormonal imbalances caused by stress or other health issues.

How the Test Works

You’ll collect all urine for a full 24-hour period in a special container. The sample is then sent to the lab for analysis to measure the total cortisol excreted in your urine.

What to Expect Before the Test

No special preparation is needed, but you should drink enough fluids to produce urine throughout the day. Avoid taking any medications that might affect cortisol levels without consulting your doctor.

What to Expect During the Test

You’ll collect your urine in a container for the entire 24-hour period. This may require reminders to empty your bladder regularly. Once complete, the sample is sent to the lab for testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

24-Hour Urine Cortisol

Frequently asked questions

High cortisol levels in urine may indicate Cushing’s syndrome, which can cause weight gain, high blood pressure, and other symptoms. Low cortisol levels may suggest adrenal insufficiency, leading to fatigue, dizziness, or low blood pressure.
This test helps confirm or rule out hormonal imbalances and guides treatment decisions, such as medication adjustments or further diagnostic testing.
What Does the Test Result Mean?
Results are compared to standard ranges for age and sex. Abnormal results may prompt additional testing, like blood cortisol levels or imaging studies, to find the cause.
Can I Take Medications Before the Test?
Some medications, like steroids or certain antidepressants, can affect cortisol levels. Always inform your doctor or lab technician about any medications 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