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Cortisol, Serum (Late Morning/Evening)

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. 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
50431-6
Short code
Cortis 6 PM SerPl-mCnc
Synonyms
Cortis 6 PM 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 this test to evaluate adrenal gland health, diagnose conditions like Cushing’s syndrome (too much cortisol) or Addison’s disease (too little cortisol), or check for issues related to stress or hormone imbalances. It’s often done at specific times of day to see how cortisol naturally fluctuates.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s a morning sample. If your doctor has specific instructions, follow them closely. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A small blood sample will be drawn from a vein, typically in your arm. The process is quick and usually painless. The sample is sent to a lab for analysis, where cortisol levels are measured using a sensitive immunoassay method.

What the Results Mean

Results are compared to standard ranges for your age and sex. Abnormally high or low levels may signal underlying health concerns, but interpretation depends on your overall health and symptoms. Your doctor will discuss these results with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Cortisol

Frequently asked questions

How often should cortisol testing be repeated?
If your doctor orders cortisol testing, they may repeat it at different times (e.g., morning, evening) or under specific conditions (e.g., after stress triggers) to get a clearer picture of your adrenal function. Follow your doctor’s instructions for follow-up testing.
What can affect cortisol test results?
Several factors can influence cortisol levels, including time of day, stress, medications (like steroids), certain foods or supplements, and medical conditions. If you’re unsure about recent stress, medications, or lifestyle changes, share this with your doctor before the test.
Is cortisol testing painful?
The blood draw itself is typically mild discomfort, but most people tolerate it well. The needle is inserted briefly, and you may feel a slight pinch. If you’re anxious about blood draws, let your doctor or nurse know so they can provide additional reassurance or techniques to help.
  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