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Cortisol Peak Concentration (24-hour Profile)

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

This test measures the highest level of cortisol, a hormone produced by your adrenal glands, during a 24-hour period. It helps assess adrenal function and rule out conditions like Cushing’s syndrome or adrenal insufficiency.

Quick summary

["A cortisol peak test helps diagnose hormonal imbalances by tracking your body’s natural cortisol fluctuations."]

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

Key facts at a glance

LOINC
9813-7
Short code
Cortis AM peak SerPl-mCnc
Synonyms
Cortis AM peak 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 recommend this test if you have symptoms like unexplained weight gain, high blood pressure, fatigue, or mood changes that could be linked to abnormal cortisol levels. It’s also used in cases where a single cortisol measurement isn’t enough to confirm a diagnosis, such as Cushing’s syndrome or adrenal disorders.

What to Expect Before the Test

No special preparation is needed, but you may be asked to collect urine samples over a full 24-hour period. Follow your healthcare provider’s instructions carefully to ensure accurate results.

How the Test Works

Your urine is collected throughout the day, and the highest cortisol concentration is measured. This peak value helps determine if your cortisol levels are consistently high or low, which can indicate hormonal imbalances.

Possible Results and Next Steps

If your cortisol peak is higher than expected, it may suggest conditions like Cushing’s syndrome. If it’s lower, it could indicate adrenal insufficiency. Your doctor will discuss the results with you and may recommend further testing or treatment options.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Cortisol Peak

Frequently asked questions

What does a high cortisol peak mean?
A high cortisol peak may indicate overproduction of cortisol, which can lead to symptoms like weight gain, muscle weakness, or high blood pressure. This could be due to conditions such as Cushing’s syndrome, where the body produces too much cortisol from an external source like a tumor.
What does a low cortisol peak mean?
A low cortisol peak may suggest adrenal insufficiency, where the adrenal glands don’t produce enough cortisol. This can cause fatigue, low blood pressure, salt cravings, or dizziness. It’s important to address this with medical guidance to prevent serious complications.
How often should I get this test?
This test is typically done once as part of a diagnostic evaluation. Follow your doctor’s advice on follow-up testing if needed, as results may guide further monitoring or treatment.
  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