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Cortisol, Serum (Mass Concentration)

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

This test measures the amount of cortisol, a natural steroid hormone produced by your adrenal glands, in your serum. Cortisol helps regulate metabolism, immune response, and stress reactions.

Quick summary

["Cortisol helps manage stress and supports normal bodily functions; abnormal levels may indicate health concerns."]

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

Key facts at a glance

LOINC
58825-1
Short code
Cortis sp18 SerPl-mCnc
Synonyms
Cortis sp18 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 Is This Test Done?

Your doctor may order this test to check for conditions like Cushing’s syndrome (too much cortisol), Addison’s disease (too little cortisol), or to evaluate stress responses, especially if you have symptoms like weight changes, fatigue, or mood swings.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample, which usually causes only mild discomfort. If you’re taking medications that affect cortisol levels, let your doctor know.

What to Expect During the Test

The blood sample will be taken by a healthcare professional, and you’ll likely feel a brief pinch. The sample is then sent to a lab for analysis. Results are typically available within a few days.

What the Results Mean

Results help determine whether your cortisol levels are too high or too low. Your doctor will compare these results to your symptoms and other tests to diagnose potential conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cortisol Level

Frequently asked questions

What causes cortisol levels to be tested?
Cortisol testing is often done if you have symptoms like unexplained weight changes, frequent infections, fatigue, or mood swings. It may also be used to monitor conditions like Cushing’s syndrome or Addison’s disease.
How long does it take to get results?
Results are usually available within 2 to 5 business days, depending on your lab’s processing time. Your doctor will contact you once they are ready to discuss the findings.
Can I eat or drink before the test?
You can eat and drink normally before this test, as no fasting is required. However, if you’re taking medications that affect cortisol levels, inform your doctor beforehand.
  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