Acthpcrhstimulationpnlplas

Published: August 9, 2026Updated: August 10, 2026

A blood test that measures how your pituitary gland responds to corticotropin-releasing hormone (CRH) to help diagnose adrenal and pituitary disorders.

Quick summary

{"Measures ACTH levels before and after CRH injection","Helps diagnose Cushing's disease and Addison's disease","Requires multiple blood samples drawn over 1-2 hours","Performed in a hospital or clinic setting","May cause temporary flushing or mild discomfort"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 10, 2026Editorial policy

Key facts at a glance

LOINC: 91707-0
Short code: ACTH-CRHP
Synonyms: ACTH p CRH stimulation Pnl Plas
Category: chemistry
Sample: serum
Container: Lavender-top EDTA plasma tube (K2-EDTA) or serum separator tube (SST) - check with laboratory specific requirements as some prefer plasma for ACTH stability
Units: N/A
Ref low: 20
Ref high: 100
Fasting: false
Population: adult
Sex: all
Age range: ≥ 18 years
Method: Chemiluminescent Immunoassay (CLIA) or Enzyme-Linked Immunosorbent Assay (ELISA)
CPT: 80412 - ACTH stimulation panel; 80436 - CRH stimulation test
SNOMED: 313295005 (ACTH measurement), 23620000 (CRH stimulation test)
Specimen volume: 1-2 mL of plasma/serum minimum; 2-3 mL recommended
Stability: ACTH is unstable in whole blood. Collect on ice, centrifuge within 30-60 minutes of collection, separate plasma/serum immediately. Store at 2-8°C if testing within 24 hours; otherwise freeze at -20°C or below. Avoid repeated freeze-thaw cycles.
Hemolysis max: 50
Lipemia max: 100
Icterus max: 20
TAT: 48–120 hours
Order: routine

What is this test?

The ACTH stimulation test, also known as the CRH stimulation test, measures how your pituitary gland responds to corticotropin-releasing hormone (CRH). CRH is a hormone that normally signals your pituitary gland to release ACTH (adrenocorticotropic hormone), which then stimulates your adrenal glands to produce cortisol. This test helps doctors understand if your pituitary and adrenal glands are working properly.

How is the test performed?

A healthcare provider will insert an intravenous (IV) line into your arm. They will draw a baseline blood sample to measure your initial ACTH and cortisol levels. Then, they will inject synthetic CRH through the IV. Additional blood samples will be drawn at specific time intervals (typically at 15, 30, 60, and 120 minutes) after the injection to measure how your hormone levels change over time. The entire procedure usually takes about 1-2 hours.

How to prepare for the test

Your doctor may ask you to fast (not eat or drink) for a certain period before the test. You should inform your doctor about all medications you are taking, as some drugs (especially steroids, hormones, or antidepressants) can affect the test results. Wear comfortable clothing with sleeves that can be easily rolled up. It's helpful to bring a book or something to pass the time during the multiple blood draws.

What will I feel during the test?

You may feel a brief pinch when the IV is inserted. Some people experience temporary flushing, warmth, or a metallic taste in the mouth after the CRH injection. These sensations are usually mild and go away quickly. The multiple blood draws may cause some minor bruising or soreness at the injection site. Overall, the test is generally well-tolerated.

Reference range

Peak ACTH response after CRH stimulation: typically 2-5 fold increase above baseline; absolute peak typically 20-100 pg/mL (4.4-22 pmol/L) depending on assay. Normal responders show significant rise within 15-30 minutes post-CRH administration.N/A

Specimen: serum

Patient should fast overnight (8-12 hours) though fasting is not strictly required. Avoid corticosteroid medications unless specifically instructed by endocrinologist. Inform about CRH administration - may cause flushing, warmth, or mild hypotension. Rest in supine position for at least 30 minutes before baseline sample collection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Why do I need this test?

Your doctor may order this test if you have symptoms of Cushing's syndrome (such as weight gain, high blood pressure, purple stretch marks, or easy bruising) or Addison's disease (such as fatigue, low blood pressure, or darkening of the skin). It helps determine whether your pituitary or adrenal glands are functioning properly.

How long does the test take?

The entire test typically takes 1-2 hours, including the IV setup, baseline blood draw, CRH injection, and subsequent blood samples taken at various time intervals.

Are there any risks or side effects?

The risks are minimal and similar to any blood test, including slight bruising, bleeding, or infection at the injection site. The CRH injection may cause temporary flushing, warmth, dizziness, or mild nausea. These side effects usually disappear quickly.

When will I get my results?

Results are usually available within a few days to a week, as the blood samples need to be analyzed in a specialized laboratory. Your doctor will discuss the results with you at a follow-up appointment.

Can I take my regular medications before the test?

Follow your doctor's specific instructions. Some medications, especially steroids, birth control pills, and certain antidepressants, can affect test results. Always inform your doctor about all medications and supplements you are taking.

Sources

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 10, 2026. · Read our editorial policy