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Cortisol — Concentration

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

Measures the amount of cortisol in a sample to help evaluate adrenal gland function and the body’s stress response.

Quick summary

["Cortisol results must be interpreted with the collection time and clinical context."]

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

Key facts at a glance

LOINC
36501-5
Short code
CT SIJ WO contr
Synonyms
CT SIJ WO contr
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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

What is this test?

Cortisol is a hormone made by the adrenal glands. It helps the body respond to stress and affects metabolism, blood sugar, immune function, and blood pressure. This test measures the concentration of cortisol in a laboratory sample.

Why might I need this test?

A clinician may order this test to investigate symptoms of excess or insufficient cortisol, assess adrenal gland function, or monitor certain steroid treatments. It may also be used when evaluating conditions that affect the pituitary gland or other parts of the hormone-regulation system.

How is the test performed?

A blood or urine sample is collected according to the test ordered by your clinician. The laboratory measures the cortisol concentration in the sample. Collection time and other testing details can be important because cortisol normally changes throughout the day.

How do I prepare for the test?

Follow your clinician’s instructions about the collection time, fasting, and whether you need to collect all urine for a specified period. Recent illness, injury, surgery, pregnancy, stress, and steroid medicines can affect results. Tell your clinician about medications and supplements, and do not stop prescribed steroids without medical advice.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cortisol

Frequently asked questions

Does the time of day affect a cortisol test?
Yes. Cortisol normally varies during the day, so your clinician may request testing at a specific time. Follow the collection instructions exactly.
Can stress or illness change my result?
Yes. Acute stress, illness, surgery, and pregnancy can temporarily increase cortisol. Tell your clinician about these circumstances when the test is ordered.
Should I stop taking steroids before this test?
No. Do not stop prescribed steroid medicines on your own. Your clinician can advise whether any testing needs to be adjusted and how to do so safely.
  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