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This blood test measures the level of adrenocorticotropic hormone (ACTH) in your blood 3 hours after receiving a glucagon injection, helping doctors evaluate how your pituitary and adrenal glands are functioning.
{"The test measures ACTH hormone levels 3 hours after a glucagon injection","It helps diagnose conditions like Cushing's disease and adrenal disorders","A blood sample is taken from a vein in your arm","You may need to fast overnight before the test","Results help doctors determine if your pituitary or adrenal glands are working properly"}
Key facts at a glance
- LOINC
- 58595-0
- Short code
- ACTH post glucagon 3hr
- Synonyms
- ACTH 3h p Gc Plas-sCnc
- Category
- chemistry
- Sample
- plasma
- Container
- Lavender top (EDTA) plastic tube
- Units
- N/A
- Ref low
- 2.2
- Ref high
- 11
- Critical range
- 1.1 N/A – 22 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Chemiluminescent Immunoassay (CLIA)
- CPT
- 82533
- SNOMED
- 386725004
- Specimen volume
- 1 mL minimum, 2 mL preferred
- Stability
- Process within 30 minutes; separate plasma and freeze at -20°C if delay >2 hours; stable frozen for up to 3 months
- Hemolysis max
- 50
- Lipemia max
- 100
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The ACTH stimulation test with glucagon measures the level of adrenocorticotropic hormone (ACTH), also called corticotropin, in your blood. ACTH is a hormone produced by the pituitary gland that tells your adrenal glands to make cortisol. This test is performed 3 hours after you receive an injection of glucagon, a hormone that stimulates the pituitary gland to release ACTH.
Why do I need this test?
Your doctor may order this test to help diagnose: Cushing's disease (when the pituitary gland makes too much ACTH), adrenal gland disorders, Addison's disease (adrenal insufficiency), or to differentiate between various causes of abnormal cortisol levels. It can also help evaluate pituitary function and detect tumors affecting the pituitary or adrenal glands.
How do I prepare for the test?
Follow these preparations: Fast overnight (usually 8-12 hours) before the test. Inform your doctor about all medications you take, especially steroids, hormone medications, or diabetes drugs. Tell your doctor if you are pregnant or have any known adrenal or pituitary conditions. Avoid strenuous exercise before the test as it may affect results. Follow any specific instructions from your healthcare provider.
What happens during the test?
First, you will receive a glucagon injection (usually in your arm or abdomen). You will then wait in the clinic for 3 hours. During this waiting period, you may need to rest quietly. After 3 hours, a healthcare professional will draw a blood sample from a vein in your arm using a small needle. The blood sample is then sent to a laboratory for analysis.
What do the results mean?
Normal results vary by laboratory. High ACTH levels after glucagon stimulation may indicate Cushing's disease, ectopic ACTH-producing tumors, or adrenal insufficiency. Low or no increase in ACTH levels may suggest adrenal tumors, pituitary insufficiency, or other adrenal disorders. Your doctor will interpret your results along with other tests and your clinical symptoms to make a diagnosis.
Are there any risks?
The risks are minimal and include slight pain or bruising at the injection site, dizziness, or fainting during blood draw. Glucagon may cause temporary side effects like nausea, vomiting, or low blood sugar. These side effects are usually mild and go away quickly. Talk to your doctor if you have concerns about the procedure.
Reference range
Reference range for ACTH 3 hours post-glucagon: 2.2-11.0 pmol/L (10-50 pg/mL); peak response typically occurs within 1-2 hours and may remain elevated at 3 hoursN/A
Patient should rest for 30 minutes prior to test. Glucagon 1mg (or 1.5mg for weight >90kg) is administered intramuscularly. Blood sample for ACTH is collected 3 hours post-glucagon administration. Patient should avoid glucocorticoids, estrogens, and ACTH-suppressing medications prior to test as per physician instructions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
How long does the entire test take?
Can I eat or drink during the 3-hour waiting period?
What medications might affect the test results?
Will I feel sick after the glucagon injection?
How soon will I get my results?
Sources
- 1MedlinePlus - ACTH TestSource
- 2
- 3
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.
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 10, 2026. · Read our editorial policy