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Cortisol (Serum or Plasma, Morning)

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

This test measures your cortisol levels in the morning to help assess your body’s ability to produce cortisol, a hormone involved in stress response, metabolism, and immune function.

Quick summary

["Morning cortisol 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
58634-7
Short code
Cortis 10 AM SerPl-sCnc
Synonyms
Cortis 10 AM SerPl-sCnc
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 Matters

Cortisol is a critical hormone that your body releases in response to stress, regulates blood sugar, and supports immune function. Morning cortisol levels can reveal whether your adrenal glands are functioning properly or if there’s an overproduction of cortisol.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning. Bring any medications you’re currently taking to your appointment.

How the Test Works

A blood sample is taken from a vein in your arm. The test measures cortisol concentration in your serum or plasma using an immunoassay method, which detects the hormone’s presence with high accuracy.

Possible Conditions Evaluated

This test helps diagnose or monitor conditions such as adrenal insufficiency (Addison’s disease), Cushing’s syndrome (high cortisol), or pituitary disorders that affect cortisol production.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Morning Cortisol Level

Frequently asked questions

What does a low cortisol level mean?
Low cortisol can signal adrenal insufficiency, where your body struggles to produce enough of this hormone. It may cause fatigue, weight loss, low blood pressure, or muscle weakness. Further testing, like an ACTH stimulation test, may be needed to confirm the diagnosis.
What does a high cortisol level mean?
High cortisol levels may indicate chronic stress, Cushing’s syndrome (from excess hormone production), or certain tumors. Symptoms could include weight gain, muscle weakness, or easy bruising. Your doctor will guide you on next steps based on your results and symptoms.
Can diet or medications affect cortisol levels?
Yes, certain medications (like steroids) or foods high in salt or caffeine can influence cortisol. If you’re on long-term medications, your doctor may adjust timing or dosage based on test results. Avoiding caffeine and heavy meals before testing can help ensure 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