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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 blood 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
1449-8
Short code
Cortis pre 8 mg Dex SerPl-mCnc
Synonyms
Cortis pre 8 mg Dex 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 healthcare provider may order a cortisol test to diagnose or monitor conditions like Cushing’s syndrome (too much cortisol), Addison’s disease (too little cortisol), or adrenal gland issues. It can also help assess stress responses or evaluate symptoms like fatigue, weight changes, or mood swings.

What to Expect Before the Test

No special preparation is usually needed, but if your test involves timing (e.g., early morning for cortisol), your provider may instruct you to fast or avoid certain medications for a few hours before. Bring any medications you’re currently taking to your appointment.

During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to general reference ranges, but your actual values will be interpreted by your provider based on your medical history and symptoms. Low cortisol may signal adrenal insufficiency, while high levels could indicate overproduction or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Cortisol plays a vital role in balancing your body’s response to stress, immune function, and metabolism. Abnormal levels can signal underlying health issues, such as hormonal imbalances, adrenal disorders, or chronic stress. Your provider will use these results alongside other tests and symptoms to guide diagnosis and treatment.

Short name

Serum Cortisol

Frequently asked questions

How often should cortisol tests be repeated if my results are abnormal?
If your cortisol levels are outside the expected range, your provider may recommend repeating the test or additional tests (like a 24-hour urine cortisol test) to confirm the diagnosis. Follow-up timing depends on your specific condition and treatment plan.
Can diet or lifestyle affect cortisol test results?
Yes, certain foods, medications (e.g., steroids), caffeine, or stress can influence cortisol levels. If your test involves timing (e.g., morning samples), avoid caffeine or heavy meals before drawing blood. Always follow your provider’s specific instructions for optimal results.
Is there any risk or discomfort with a blood draw for cortisol testing?
The blood draw itself is generally quick and well-tolerated, but you might feel slight discomfort or bruising at the injection site. Rarely, some people experience fainting or excessive bleeding. If you have a hard time with needles, let your provider know so they can prepare accordingly.
  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