Acthrhserplscnc

Published: August 9, 2026Updated: August 15, 2026

This test measures the level of corticotropin releasing hormone (CRH) in your blood to help evaluate how well your hypothalamus-pituitary-adrenal (HPA) axis is functioning.

Quick summary

{"CRH is a hormone produced by the hypothalamus that controls cortisol release","The test helps diagnose conditions related to adrenal gland function","Blood sample is typically collected in the morning when CRH levels are highest","Results help differentiate between various causes of cortisol disorders","You may need to fast or avoid certain medications before the test"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC: 37990-9
Short code: CRH
Synonyms: ACTH RH SerPl-sCnc
Category: chemistry
Sample: serum
Container: Lavender top (EDTA) tube or serum separator tube (SST)
Units: N/A
Ref low: 1
Ref high: 10
Fasting: false
Population: adult
Sex: all
Age range: 18–65 years
Method: Immunoassay (Chemiluminescence or ELISA)
CPT: 80448
SNOMED: 413541009
Specimen volume: 1-2 mL of serum or plasma
Stability: Separate plasma or serum from cells within 1 hour of collection. Store at 2-8°C if testing within 24 hours; freeze at -20°C or below for longer storage. Avoid repeated freeze-thaw cycles.
Hemolysis max: 50
Lipemia max: 100
Icterus max: 20
TAT: 48–168 hours
Order: routine

What is the CRH Test?

The corticotropin releasing hormone (CRH) test measures the amount of CRH in your blood. CRH is a hormone produced by a part of the brain called the hypothalamus. Its main job is to tell another gland (the pituitary gland) to release ACTH (adrenocorticotropic hormone), which then signals the adrenal glands to produce cortisol, the body's primary stress hormone.

Why is it Performed?

This test is primarily used to evaluate the function of the hypothalamus-pituitary-adrenal (HPA) axis. Your healthcare provider may order this test if you have symptoms of abnormal cortisol levels, such as excessive weight gain (especially around the neck and face), high blood pressure, high blood sugar, or conversely, extreme fatigue, weight loss, and low blood pressure. It helps doctors determine if a problem originates in the hypothalamus, pituitary gland, or adrenal glands.

How is the Test Done?

A healthcare professional will draw a blood sample from a vein in your arm, usually in the morning when hormone levels are at their peak. The blood is collected into a special tube and sent to a laboratory for analysis. The procedure is quick and similar to other routine blood tests. You may be asked to fast for several hours before the test and to avoid certain medications that could affect the results, such as steroids or birth control pills.

What Do the Results Mean?

Abnormal CRH levels can indicate different conditions. Low CRH levels may suggest a problem with the hypothalamus or may occur with long-term use of steroid medications. High CRH levels might indicate a tumor producing CRH, inflammatory conditions, or severe stress. Your doctor will interpret your results alongside other hormone tests (like cortisol and ACTH) and your clinical symptoms to make an accurate diagnosis.

Are There Any Risks?

The risks associated with this test are minimal and similar to any routine blood draw. You may experience slight bruising at the puncture site, lightheadedness, or in rare cases, infection. The benefits of obtaining important diagnostic information generally far outweigh these minimal risks.

Reference range

Reference range varies by methodology and laboratory; typically 1-10 pmol/L for healthy adults. Each laboratory should establish its own reference range.N/A

Specimen: serum

No special preparation required. Avoid medications that may affect ACTH/cortisol levels for at least 48 hours prior to collection if possible. Inform laboratory of any current medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Do I need to prepare specially for the CRH test?

Yes, you may need to fast (not eat or drink except water) for 8-12 hours before the test. Your doctor may also ask you to stop certain medications like steroids, anti-inflammatory drugs, or birth control pills, as these can affect hormone levels. Always follow your healthcare provider's specific instructions.

Is the test painful?

The test involves a needle prick to draw blood, which may cause brief discomfort or a slight sting. This sensation typically lasts only a few seconds. The procedure is performed by trained professionals to minimize any pain or complications.

How long does it take to get results?

Results are usually available within a few days to a week, depending on the laboratory. Your healthcare provider will contact you with the results or discuss them at your follow-up appointment.

What conditions are associated with abnormal CRH levels?

Abnormal CRH levels can be associated with Cushing's disease, ectopic ACTH-producing tumors, adrenal insufficiency, hypothalamic disorders, and certain inflammatory conditions. Your doctor will interpret the results in context with other hormone tests and your symptoms.

Can I eat or drink normally after the test?

Yes, once the blood sample is collected, you can resume your normal activities and diet. If you fasted before the test, you may want to have a meal or snack afterward to prevent lightheadedness.

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 15, 2026. · Read our editorial policy