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Cortisol, Serum (12 PM)

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

This test measures cortisol levels in your blood at 12 PM, often used to evaluate adrenal function and stress responses.

Quick summary

["Cortisol is a hormone that helps regulate stress and metabolism; this test helps assess your body’s ability to produce it."]

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

Key facts at a glance

LOINC
45048-6
Short code
Cortis 12 PM SerPl-sCnc
Synonyms
Cortis 12 PM 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 Is This Test Done?

Your healthcare provider may order this test to check for conditions like Cushing’s syndrome (too much cortisol), adrenal insufficiency (too little cortisol), or to monitor treatment for hormone-related disorders. It can also help diagnose stress-related issues or rule out other causes of fatigue or weight changes.

What Does the Test Involve?

A blood sample is taken from a vein in your arm. You’ll typically fast for 8–12 hours before the test to ensure accurate results. The sample is sent to a lab for measurement using an immunoassay method.

What to Expect Before the Test

No special preparation is needed beyond fasting if instructed. Wear comfortable clothing and plan to rest for a few minutes after the blood draw. If you’re pregnant, have a chronic condition, or take certain medications, let your provider know.

What Are Common Results?

Results are reported as a concentration of cortisol in your serum. Your provider will compare these results to your individual baseline and clinical picture to determine if further action is needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

What Does High or Low Cortisol Mean?
High cortisol levels may indicate conditions like Cushing’s syndrome, chronic stress, or certain tumors. Low cortisol can signal adrenal insufficiency, which may require hormone replacement therapy or treatment of underlying causes like autoimmune disorders.
What If My Results Are Abnormal?
If your results are outside expected ranges, your provider may recommend additional tests (like a 24-hour urine cortisol test) or further evaluation to identify the cause. Follow-up may include lifestyle adjustments, medication, or referral to a specialist.
How Often Should I Get This Test?
The frequency depends on your health status. If you have a known condition, your provider may schedule it regularly. If it’s a one-time screening, results will guide future testing needs.
  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