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Cortisol, Free Serum (24-Hour Urinary)

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

This test measures the amount of free cortisol (the active form) excreted in your urine over a 24-hour period. It helps assess whether your body is producing too much or too little cortisol, often linked to conditions like Cushing’s syndrome or adrenal insufficiency.

Quick summary

["This test helps diagnose hormonal imbalances affecting stress response and metabolism."]

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

Key facts at a glance

LOINC
50422-5
Short code
Cortis 20M p 100 ug CRH IV SerPl-mCnc
Synonyms
Cortis 20M p 100 ug 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 you have symptoms like unexplained weight changes, fatigue, high blood pressure, or signs of hormonal disorders. It’s also used to monitor conditions like Cushing’s syndrome or adrenal gland issues before or after treatment.

What to Expect Before the Test

You’ll need to collect all urine for a full 24 hours, typically starting after midnight and ending the next midnight. Drink plenty of fluids to ensure adequate urine production. Avoid certain medications (like some steroids) that could affect results, and inform your doctor about any supplements or over-the-counter drugs you’re taking.

What Happens During the Test

You’ll provide a single urine sample at the end of the 24-hour period. The lab will analyze the sample for free cortisol levels. No special preparation is needed beyond collecting urine in a sterile container at home or at a clinic.

What the Results Mean

Results are compared to standard ranges, but interpretation depends on your symptoms and medical history. High levels may suggest Cushing’s syndrome or excessive stress, while low levels could indicate adrenal insufficiency or other hormonal disorders. Your doctor will discuss findings with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Free Cortisol Urine Test

Frequently asked questions

What causes elevated cortisol levels in urine?
Elevated cortisol in urine can result from conditions like Cushing’s syndrome (due to excess cortisol production), prolonged stress, or certain medications (e.g., steroids). It may also occur in people with pituitary tumors or adrenal gland disorders.
What causes low cortisol levels in urine?
Low cortisol in urine may indicate adrenal insufficiency (e.g., Addison’s disease), where the adrenal glands don’t produce enough cortisol. It can also occur after adrenal surgery, radiation, or long-term steroid use.
How often should I get this test?
Your doctor will determine the frequency based on your symptoms, medical history, and treatment needs. Follow-up tests may be scheduled if initial results are abnormal or if you’re undergoing treatment for a condition like Cushing’s syndrome or adrenal dysfunction.
  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