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Cortisol (serum/plasma, quantitative 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 helps manage stress and supports normal bodily functions."]

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

Key facts at a glance

LOINC
20995-7
Short code
Cortis 1h p ACTH SerPl-Imp
Synonyms
Cortis 1h p ACTH SerPl-Imp
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 healthcare provider may order cortisol testing to diagnose or monitor conditions like adrenal gland disorders (such as Cushing’s syndrome or Addison’s disease), evaluate stress responses, or check for hormonal imbalances. It can also be used in situations where cortisol levels fluctuate, such as during sleep studies or to assess pituitary function.

What to Expect During the Test

A blood sample is taken from a vein in your arm. You may feel a slight pinch or discomfort, but it usually takes only a few minutes. No special preparation is typically needed unless instructed otherwise by your provider.

Sample Collection and Processing

The blood sample is collected in a special tube that separates serum or plasma from blood cells. The sample is then sent to a lab for analysis using an immunoassay method to measure cortisol concentration accurately.

What the Results Mean

Results may be reported as a single value or in different timeframes (e.g., morning vs. evening levels). High or low cortisol levels can indicate underlying health issues, but interpretation depends on clinical context and other test results.

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

Cortisol Level

Frequently asked questions

High cortisol levels might suggest conditions like Cushing’s syndrome, where the body produces too much cortisol, or chronic stress. Low cortisol levels could indicate adrenal insufficiency, where the adrenal glands don’t produce enough cortisol, or problems with the pituitary gland.
Cortisol testing can help diagnose hormonal imbalances, evaluate stress responses, and guide treatment for conditions affecting the adrenal or pituitary glands. It’s important to discuss your results with your healthcare provider, as they’ll consider your full medical history and other tests.
How often should cortisol levels be checked?
The frequency of cortisol testing depends on your medical condition and treatment plan. Some people may need testing once or twice a year, while others with chronic conditions might require more frequent monitoring. Always follow your healthcare provider’s recommendations.
What factors can affect cortisol test results?
Several factors can influence cortisol levels, including time of day (morning levels are often higher), stress, certain medications (like steroids), illness, or even recent physical activity. If you’re taking medications or have recent health changes, let your provider know before the test.
  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