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Cortisol, Serum Free (24-Hour Urinary Excretion)

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

This test measures the amount of free cortisol naturally excreted in your urine over 24 hours. It helps assess how well your body produces cortisol, a hormone involved in stress response and metabolism.

Quick summary

["Helps diagnose adrenal gland disorders by checking cortisol levels over a full day."]

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

Key facts at a glance

LOINC
58827-7
Short code
Cortis sp16 SerPl-mCnc
Synonyms
Cortis sp16 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 doctor may order this test if they suspect conditions like Cushing’s syndrome (overproduction of cortisol) or Addison’s disease (underproduction). It’s also used to monitor treatment for these conditions or evaluate stress-related hormone imbalances.

What to Expect Before the Test

You’ll collect all urine for 24 hours, starting right after midnight of one day and ending right before midnight the next. Store samples in a refrigerator until you take them to the lab. Follow any specific instructions your healthcare provider gives you, such as avoiding certain medications.

What Happens During the Test

No special preparation is needed beyond the 24-hour urine collection. The lab will analyze the sample for free cortisol levels, which are then compared to expected ranges.

How the Results Are Used

High cortisol levels may indicate overactivity of the adrenal glands or pituitary gland, while low levels could signal adrenal insufficiency or other hormonal issues. Your doctor will interpret results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Cortisol Urine Test

Frequently asked questions

What does a high cortisol level mean?
A high cortisol level may suggest conditions like Cushing’s syndrome, prolonged stress, or certain tumors affecting hormone production. Your doctor will discuss next steps, which could include additional tests or treatments.
What does a low cortisol level mean?
Low cortisol levels could indicate Addison’s disease, adrenal insufficiency, or autoimmune disorders. This result may prompt further testing, such as blood cortisol measurements or other hormone evaluations.
How often should I get this test?
Your doctor will determine the frequency based on your symptoms, medical history, and previous test results. Follow-up tests may be needed if initial results are abnormal or if you’re under treatment for a condition related to cortisol.
  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