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Cortisol (Serum or Plasma) Measurement

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of cortisol, a natural steroid hormone produced by your adrenal glands. Cortisol helps regulate metabolism, immune response, and stress reactions.

Quick summary

["Cortisol levels help diagnose adrenal gland disorders and stress-related conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
47850-3
Short code
Cortis p ACTH SerPl-mCnc
Synonyms
Cortis p ACTH SerPl-mCnc
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
60
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 Might Be Ordered

Your doctor may recommend this test if you have symptoms like unexplained weight changes, fatigue, high blood pressure, or irregular menstrual periods. It could also be used to check for conditions like Cushing’s syndrome (too much cortisol) or Addison’s disease (too little cortisol).

What to Expect Before the Test

No special preparation is needed, but if you’re taking medications that affect cortisol levels (like steroids), let your doctor know. You’ll provide a blood sample, usually drawn from a vein in your arm.

What the Results Mean

Results help determine if your adrenal glands are functioning normally. Abnormal levels may indicate hormonal imbalances that require further medical evaluation.

Common Conditions Linked to Cortisol Testing

High cortisol levels may be linked to conditions like Cushing’s syndrome, while low levels could signal Addison’s disease or other adrenal disorders. Stress, certain medications, and pregnancy can also influence cortisol levels.

Reference range

NCBI: ACTH 10-60 pg/mLN/A

Specimen: serum

Typically collected in the morning (8-10 AM). Inform your provider if taking steroid medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Serum Cortisol

Frequently asked questions

What triggers cortisol testing?
Cortisol testing is often triggered by symptoms like persistent fatigue, unexplained weight gain or loss, high blood pressure, or changes in your menstrual cycle. Doctors may also order it to investigate suspected adrenal disorders or to monitor conditions like Cushing’s syndrome or Addison’s disease.
How is cortisol tested?
Cortisol is measured in a blood sample, usually taken from a vein in your arm. No special preparation is needed, but if you’re on medications that affect cortisol levels, inform your healthcare provider beforehand.
Can cortisol levels change with stress?
Yes, cortisol levels naturally rise in response to stress. However, if your body consistently produces too much or too little cortisol, it may indicate an underlying medical condition that requires evaluation.
  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 17, 2026. · Read our editorial policy