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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 gland function and potential stress-related conditions."]

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

Key facts at a glance

LOINC
58819-4
Short code
Cortis sp21 SerPl-mCnc
Synonyms
Cortis sp21 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 check for conditions like Cushing’s syndrome (too much cortisol), Addison’s disease (too little cortisol), or to evaluate how your body responds to stress or medications that affect cortisol levels.

What Does the Test Involve?

You’ll have a blood sample drawn from a vein, usually in your arm. The sample is sent to a lab for analysis to measure cortisol concentration.

What Are Common Reasons for Testing?

Tests may be performed during the morning (when cortisol is typically highest) or at other times if your symptoms or medical history suggest variations in cortisol levels throughout the day.

How Is the Test Performed?

The test uses a blood sample to measure cortisol mass concentration, often analyzed via immunoassay or similar methods to detect the hormone’s presence.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Cortisol

Frequently asked questions

What might cause abnormal cortisol levels?
Abnormal results could be due to conditions like Cushing’s syndrome (overproduction), Addison’s disease (underproduction), or stress-related fluctuations. Your doctor will interpret results in the context of your symptoms and medical history.
How soon will I get my results?
Results are typically available within 1–3 business days, depending on lab processing times. Your healthcare provider will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
Standard fasting is not required unless your doctor specifies otherwise. Follow any special instructions they provide, as cortisol levels can be influenced by diet, time of day, or certain medications.
  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