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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 keeps your body functioning properly."]

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

Key facts at a glance

LOINC
50458-9
Short code
Cortis sp6 SerPl-mCnc
Synonyms
Cortis sp6 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 Might This Test Be 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 fatigue, weight changes, or mood swings.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if cortisol is measured at specific times (e.g., morning or evening). Bring any medications you’re taking to your appointment.

How the Test Works

A blood sample is taken from a vein in your arm. The sample is sent to a lab where cortisol levels are measured using a sensitive immunoassay technique to detect tiny amounts in your serum.

What the Results Mean

Results are compared to general reference ranges, but values can vary based on timing (e.g., cortisol peaks in the morning). Your doctor will interpret results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cortisol Level

Frequently asked questions

Will I feel pain or discomfort during the blood draw?
You may feel a slight pinch or sting when the needle is inserted, but it usually goes away quickly. Most people experience minimal discomfort afterward.
How long will I need to wait for my results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will contact you once they’re ready.
Can I eat or drink before the test?
If fasting is required (e.g., for morning cortisol), avoid food and liquids except water for 8–12 hours beforehand. If no fasting is needed, you can eat and drink normally.
  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