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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 levels help assess adrenal function and potential stress-related conditions."]

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

Key facts at a glance

LOINC
57464-0
Short code
Cortis sp11 SerPl-mCnc
Synonyms
Cortis sp11 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 (overactive adrenal glands), Addison’s disease (underactive adrenal glands), or adrenal insufficiency. It can also help evaluate stress responses, hormone imbalances, or evaluate symptoms like fatigue, weight changes, or unusual hair growth.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if timing your cortisol levels around certain times of the day (e.g., morning or evening) is important. Bring any medications you’re currently taking to your appointment.

What Happens 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 then sent to a lab for analysis.

What Are Possible Results?

Results are interpreted by your provider based on your symptoms, medical history, and other test results. Abnormal levels may indicate conditions affecting your adrenal glands or stress responses, but they don’t stand alone for diagnosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Serum Cortisol

Frequently asked questions

What does cortisol measure?
Cortisol measures the concentration of cortisol in your blood, which reflects how your adrenal glands are producing this hormone. Elevated levels may suggest conditions like Cushing’s syndrome or excessive stress, while low levels could indicate adrenal insufficiency or other hormonal imbalances.
How is cortisol tested?
Cortisol is tested using a blood sample drawn from a vein. Some tests may be timed (e.g., morning or evening) to assess natural fluctuations, while others may be done as a single measurement or over 24 hours for more detailed evaluation.
Can cortisol levels change with stress?
Yes, cortisol levels naturally rise in response to stress, but they can also be affected by medical conditions, medications, or even sleep patterns. Your provider will consider these factors when interpreting your results.
  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