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Cortisol, Serum (8 AM)

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

This test measures your cortisol hormone level in your blood at 8 AM to help assess your body’s ability to produce cortisol, which is important for managing stress, immune function, and other vital processes.

Quick summary

["A cortisol test helps diagnose conditions like adrenal insufficiency or Cushing’s syndrome."]

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

Key facts at a glance

LOINC
12563-3
Short code
Cortis sp8 p chal SerPl-mCnc
Synonyms
Cortis sp8 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 This Test Is Done

Your doctor may order this test if you have symptoms of hormonal imbalances, such as fatigue, weight changes, or unexplained stress responses. It’s also used to evaluate conditions like Addison’s disease (adrenal insufficiency) or Cushing’s syndrome (too much cortisol).

What to Expect Before the Test

No special preparation is needed, but you should fast for 8–12 hours before the test (except for water). Your blood will be drawn from a vein in your arm, similar to other blood tests. The process takes a few minutes, and you may feel a brief pinch during the draw.

What the Results Mean

Results are compared to standard reference ranges for cortisol levels at 8 AM. Low levels may indicate adrenal insufficiency, while very high levels could suggest Cushing’s syndrome or other hormonal disorders. Your doctor will interpret the results in the context of your symptoms and medical history.

Common Conditions This Test Helps Diagnose

This test is critical in diagnosing conditions like primary adrenal insufficiency (Addison’s disease), secondary adrenal insufficiency, and Cushing’s syndrome. It can also help rule out other causes of fatigue, stress-related symptoms, or unexplained weight changes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Morning cortisol level

Frequently asked questions

What does my cortisol level tell me about my health?
A cortisol test at 8 AM helps assess whether your body produces enough cortisol to meet daily needs. Low levels may signal adrenal fatigue or autoimmune adrenal disease, while persistently high levels could indicate overproduction (e.g., from a pituitary tumor or long-term steroid use). Your doctor will use these results alongside other tests and symptoms to guide treatment.
How often should I get this test?
The frequency depends on your symptoms and diagnosis. If you have a known condition like Addison’s disease, your doctor may recommend regular monitoring. If this is a screening test, it may be done once unless you develop new symptoms. Always follow your healthcare provider’s advice.
Can I take medications before this test?
Some medications (like steroids) can affect cortisol levels. If you’re on long-term medications, discuss this with your doctor before the test. They may adjust timing or recommend temporary changes to avoid interference.
  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