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Adrenocorticotropic hormone (ACTH) measured in plasma

Published: August 9, 2026Updated: August 17, 2026

This test checks the amount of ACTH, a hormone produced by your pituitary gland, in your blood plasma. ACTH helps regulate cortisol production in your adrenal glands.

Quick summary

["ACTH levels help diagnose and monitor conditions affecting the pituitary or adrenal glands."]

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

Key facts at a glance

LOINC
1368-0
Short code
ACTH pre Ins IV Plas-mCnc
Synonyms
ACTH pre Ins IV Plas-mCnc
Category
hormone
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
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 Is Done

Your doctor may order a plasma ACTH test to evaluate symptoms such as weight changes, fatigue, high blood pressure, or unusual hair growth. It’s also used to check for conditions like Cushing’s syndrome (excess cortisol) or Addison’s disease (low cortisol). Sometimes, it’s done to investigate unexplained adrenal or pituitary issues.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8 hours before the test if cortisol levels are also being checked together. Wear comfortable clothing and bring your medical records if you have any known conditions.

What Happens During the Test

A healthcare provider will insert a small needle into a vein in your arm to draw blood. You may feel a slight pinch, but it usually doesn’t cause pain. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are interpreted by your doctor based on your symptoms and medical history. Very high or very low ACTH levels can indicate specific hormonal imbalances or underlying health issues.

Reference range

NCBI: ACTH 10-60 pg/mLN/A

Specimen: plasma

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

Plasma ACTH Level

Frequently asked questions

What are the normal reference ranges for this test?
ACTH reference ranges can vary by lab and testing method. Your doctor will use your specific results in the context of your symptoms and overall health to determine if levels are within normal limits or if further testing is needed.
Can I take anything before my ACTH test?
If your doctor hasn’t specified otherwise, avoid caffeine or stress-inducing activities 24 hours before the test. Some tests may require fasting, so follow your doctor’s instructions carefully.
How long will it take to get my results?
Results are typically available within 1 to 3 business days, depending on your lab. Your doctor will discuss the findings with you during a follow-up visit.
  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