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Cortisol (serum/plasma, 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. Cortisol helps regulate metabolism, immune response, and stress reactions.

Quick summary

["Cortisol helps manage stress and supports normal bodily functions."]

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

Key facts at a glance

LOINC
12567-4
Short code
Cortis 1h p chal SerPl-mCnc
Synonyms
Cortis 1h p chal 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 cortisol testing 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 levels or evaluate symptoms like weight changes, fatigue, or unusual mood swings.

What to Expect Before the Test

No special preparation is needed for a cortisol blood test. You may have blood drawn from a vein in your arm. If testing cortisol in urine over 24 hours, follow your doctor’s instructions for collecting samples at home.

What the Results Mean

Results are compared to standard ranges for cortisol in serum/plasma. High or low levels may indicate underlying health concerns that need further evaluation, such as hormonal imbalances or medical conditions.

Common Conditions Affecting Cortisol Levels

Conditions like Cushing’s syndrome (caused by excess cortisol) or Addison’s disease (caused by insufficient cortisol) can lead to abnormal test results. Stress, certain medications, or thyroid disorders may also influence cortisol levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cortisol Level

Frequently asked questions

What triggers cortisol testing?
Cortisol testing may be triggered by symptoms like unexplained weight changes, fatigue, high blood pressure, or unusual mood swings. Doctors also use it to diagnose conditions like Cushing’s syndrome or Addison’s disease, especially after a suspected hormonal imbalance or exposure to stress.
How is cortisol tested?
Cortisol is typically measured in a blood sample (serum or plasma) or a 24-hour urine collection. Blood tests are often done early in the morning when cortisol is usually highest. Urine tests measure total cortisol over a full day.
Can cortisol levels change with diet or exercise?
Yes, cortisol levels can be influenced by stress, sleep patterns, and certain medications. Avoiding extreme stress or caffeine before testing can help provide more accurate 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