Quick Facts
- Sample: Blood (plasma)
- Fasting: No fasting required. Blood must be drawn before 10 a.m. Stop biotin consumption at least 72 hours prior to collection.
- Turnaround: 2-5 days. May take longer due to weather, holidays, or lab delays.
What This Test Measures
This test measures the level of adrenocorticotropic hormone (ACTH) in your plasma. ACTH is a stimulating hormone produced by the pituitary gland. When cortisol levels drop, the hypothalamus signals the pituitary to release ACTH, which then prompts the adrenal glands to produce cortisol. This test measures ACTH itself, not cortisol, so it reflects the signal that drives cortisol production rather than cortisol output.
Because ACTH and cortisol typically move in opposite directions, healthcare providers often use this ACTH result alongside a separate cortisol test to help evaluate how your hypothalamus, pituitary, and adrenal glands are working together.
Benefits
- Measures ACTH, the pituitary hormone that signals cortisol production
- Helps evaluate the source of abnormal cortisol regulation
- Supports monitoring of conditions tied to pituitary or adrenal function
- Pairs with cortisol testing for a fuller picture of the pathway
- Convenient blood draw with clear preparation instructions
Who Is This Test For?
- People with symptoms of excess cortisol, such as sudden weight gain
- People noticing fat buildup in the shoulders or new stretch marks
- People with symptoms of low cortisol, like fatigue or salt cravings
- People experiencing unexplained nausea, dizziness, or abdominal pain
- Anyone whose healthcare provider is investigating pituitary or adrenal function
- People being monitored for a known cortisol-related condition
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this hormone test?
This test measures ACTH, a stimulating hormone released by the pituitary gland that prompts the adrenal glands to produce cortisol. The result may help a healthcare provider evaluate how the hypothalamus, pituitary, and adrenal glands are regulating cortisol. It does not measure cortisol directly, and it is not used on its own to diagnose a condition.
2. Who would benefit from this test?
This test may be useful for people experiencing symptoms linked to abnormal cortisol levels, such as unexplained weight changes, fatigue, muscle weakness, or changes in skin appearance. It may also benefit people whose healthcare provider wants to monitor a known issue involving the pituitary or adrenal glands.
3. When should I order this test?
You might consider this test if you are experiencing symptoms associated with excess or insufficient cortisol, or if a healthcare provider is evaluating your pituitary or adrenal function. It is often ordered alongside cortisol testing to help clarify where an imbalance may be originating.
4. How does this test differ from other hormone tests?
This test measures ACTH, a stimulating hormone, rather than cortisol, the target hormone that ACTH regulates. ACTH and cortisol typically move in opposite directions, so an ACTH result on its own does not indicate what your cortisol level is. Reviewing both together gives a more complete picture of the signaling pathway between them.
5. Do I need to fast before this test?
No fasting is required. Blood must be drawn before 10 a.m., and you should stop biotin consumption at least 72 hours prior to your collection.
6. How quickly will I get results?
Results are typically available in 2-5 days. Turnaround may take longer due to weather, holidays, or lab delays.
7. How do I interpret the results?
The meaning of your ACTH result depends on your individual symptoms, medical history, the timing of your blood draw, and other lab results, particularly cortisol. Because ACTH is a stimulating hormone, it reflects pituitary signaling rather than the cortisol level itself, and it is often interpreted alongside cortisol testing. One abnormal ACTH result does not automatically confirm a hormonal condition, and one normal result does not rule one out. Discuss your results with a qualified healthcare provider for guidance specific to your situation.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
8. What should I do if my results are abnormal?
Share your results with a qualified healthcare provider, who can review them alongside your symptoms and other test results. They can help determine whether additional evaluation or testing is needed. Do not stop prescribed medication unless instructed by your healthcare provider.
9. How often should I get tested?
Testing frequency should be determined as directed by your healthcare provider, based on your individual symptoms and health history.
Pre-test preparation
No fasting is required. Blood must be drawn before 10 a.m. Patients should stop biotin consumption at least 72 hours prior to the collection.
Do not stop prescribed medication unless instructed by your healthcare provider.
