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Cortisol (Serum)

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, and this test helps assess adrenal gland health or hormone imbalances."]

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

Key facts at a glance

LOINC
72392-4
Short code
Cortis/Cortisone SerPl
Synonyms
Cortis/Cortisone SerPl
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

Doctors may order cortisol tests to diagnose conditions like Cushing’s syndrome (too much cortisol), Addison’s disease (too little cortisol), or adrenal gland problems. It can also help evaluate stress responses or hormone-related symptoms like fatigue, weight changes, or mood swings.

What to Expect Before the Test

No special preparation is needed, but if you’re taking medications that affect cortisol (like steroids), your doctor may ask you to stop them temporarily. Bring a list of all medications to your appointment.

During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes. The blood sample is sent to a lab for analysis.

Possible Results & Next Steps

Results are compared to general reference ranges, but your doctor will interpret them based on your symptoms and medical history. High or low cortisol levels may lead to further testing, like a 24-hour urine cortisol test or a dexamethasone suppression test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cortisol Level

Frequently asked questions

What Does Cortisol Mean for My Health?
High cortisol levels may suggest conditions like Cushing’s syndrome, where the body produces too much cortisol, or chronic stress. Low cortisol levels could indicate Addison’s disease or adrenal insufficiency. Your doctor will discuss findings with you and recommend next steps, such as additional tests or treatment options.
How Often Should I Get This Test?
The frequency depends on your symptoms and medical needs. If you have an ongoing condition like adrenal dysfunction, your doctor may schedule follow-up tests regularly. If this is a one-time test, results will guide future care.
Can I Eat or Drink Anything Before the Test?
You can eat and drink normally before the test unless instructed otherwise. Avoid caffeine or alcohol for a few hours before your appointment, as they can temporarily affect cortisol levels.
  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