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Cortisol, 30-minute post-corticotropin (ACTH) stimulation test (serum/plasma)

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

This test measures your cortisol levels after you receive a dose of ACTH hormone to check how your body responds to stress. It helps diagnose conditions like adrenal insufficiency or cortisol-producing tumors.

Quick summary

["Assesses how well your adrenal glands produce cortisol in response to stress."]

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

Key facts at a glance

LOINC
58664-4
Short code
Cortis 30M pre 1 ug/kg CRH IV SerPl-sCnc
Synonyms
Cortis 30M pre 1 ug/kg CRH IV 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
CPT
86701
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 order this test if you have symptoms of adrenal problems, such as fatigue, low blood pressure, or unexplained weight loss. It can also help rule out conditions like Cushing’s syndrome or Addison’s disease.

What to Expect Before the Test

You’ll receive an injection of ACTH hormone, and your blood will be drawn 30 minutes later to check cortisol levels. Avoid caffeine or stress before the test to get accurate results.

What the Results Mean

Low cortisol levels after stimulation may indicate adrenal insufficiency, while very high levels could suggest a cortisol-producing tumor or other issues. Your doctor will interpret results in relation to your symptoms and other tests.

Common Conditions This Test Helps Diagnose

This test helps diagnose adrenal gland disorders, including primary adrenal insufficiency (Addison’s disease) and conditions like Cushing’s syndrome, where the body produces too much cortisol.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Cortisol is a hormone produced by the adrenal glands that helps regulate metabolism, immune response, and stress reactions. The ACTH stimulation test helps determine if your adrenal glands are functioning normally or if they’re overproducing or underproducing cortisol.

Short name

ACTH Stimulation Test (Cortisol)

Frequently asked questions

What triggers this test?
This test is typically triggered by symptoms like chronic fatigue, unexplained weight changes, or signs of hormonal imbalances. Doctors may also recommend it if other tests (like morning cortisol levels) are inconclusive.
How long does it take to get results?
Results are usually available within 1–3 business days, depending on your lab. Your doctor will discuss them with you during a follow-up visit.
Can I eat or drink before this test?
You can eat a normal meal, but avoid caffeine or alcohol before the test to prevent affecting your cortisol levels.
  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