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First comprehensive guideline on using biomarkers for monitoring Crohn’s disease

New AGA guideline outlines reliable blood and stool tests to monitor inflammation that can reduce how often patients need invasive endoscopy.

Bethesda, MD (Nov. 17, 2023) — The American Gastroenterological Association (AGA) released a new evidence-based guideline recommending the use of blood and stool-based biomarkers to help manage Crohn’s disease, a type of inflammatory bowel disease (IBD). IBD is estimated to affect 2.74 million people in the U.S. The guideline was published today in Gastroenterology. 

Biomarkers are blood or stool tests that can give more information on an underlying disease process. In the context of IBD, biomarkers such as C-reactive protein (CRP) in blood and fecal calprotectin (FCP) in stool, can measure levels of inflammation. These levels can help doctors assess whether a patient’s Crohn’s disease is active or in remission. 

AGA recommends the use of biomarkers in addition to colonoscopy and imaging studies. 

“Patients’ symptoms do not always match endoscopic findings, so biomarkers are a useful tool to understand and monitor the status of inflammation and guide decision making in patients with Crohn’s disease,” says guideline author Siddarth Singh, MD, MS, University of California, San Diego.  

For patients in remission: 

  • Check CRP and FCP every six to 12 months. 
  • These tests work best if CRP and FCP levels have previously matched with disease activity seen on endoscopic assessment. 

For patients experiencing active symptoms: 

  • Check CRP and FCP every two to four months for patients experiencing an increase in symptoms (diarrhea and abdominal pain) to guide treatment adjustments. 
  • Before making any major treatment plan changes, consider repeating endoscopic or radiologic assessments. 

For patients after surgery:  

  • FCP may be useful to monitor patients at low risk for disease recurrence. 
  • However, radiologic or endoscopic assessment should be performed when a post-operative recurrence is suspected rather than relying on biomarkers. 

“Based on this guideline, biomarkers are no longer considered experimental and should be an integral part of IBD care,” says guideline author Ashwin Ananthakrishnan, MBBS, MPH, Massachusetts General Hospital. 

This is a win for Crohn’s disease patients. Biomarkers are usually easier to obtain, less invasive, more cost-effective than frequent colonoscopies and can be assessed more frequently for tighter disease control and better long-term outcomes in Crohn’s disease.” 

About Crohn’s disease 

Crohn’s disease is a chronic inflammatory condition that can affect any part of the digestive tract, from the mouth to the anus. It causes inflammation and damage to the digestive system, leading to symptoms such as abdominal pain, diarrhea, weight loss and fatigue and complications such as strictures and fistulas. Crohn’s disease is a lifelong condition with periods of active symptoms (flare-ups) and periods of remission when symptoms are less severe or absent. It can be diagnosed at any age but is most often diagnosed between ages 13 and 30. It can vary in severity and usually requires ongoing medical management to control symptoms and improve quality of life. Learn more in the AGA GI Patient Center. 



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Media contact: Mara Shapiro, [email protected] 

About the AGA Institute 

The American Gastroenterological Association is the trusted voice of the GI community. Founded in 1897, the AGA has grown to more than 16,000 members from around the globe who are involved in all aspects of the science, practice and advancement of gastroenterology. The AGA Institute administers the practice, research and educational programs of the organization. 

About Gastroenterology 

Gastroenterology is the most prominent journal in the field of gastrointestinal disease. As the official journal of the AGA Institute, Gastroenterology delivers up-to-date and authoritative coverage of both basic and clinical gastroenterology. Regular features include articles by leading authorities and reports on the latest treatments for diseases. Original research is organized by clinical and basic-translational content, as well as by alimentary tract, liver, pancreas, and biliary content. 

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