Clinical recommendation	Evidence rating	Comments
A normal C-reactive protein or fecal calprotectin level effectively rules out inflammatory bowel disease for patients who meet Rome IV diagnostic criteria for irritable bowel syndrome without alarm features.1,3,13,30	A	Good-quality meta-analysis and clinical guidelines
Serologic testing should be performed for celiac disease in all patients presenting with chronic diarrhea.1,3,8	C	Evidence-based guidelines, consistent retrospective evidence
Clinicians testing for Clostridioides difficile infection should examine only diarrheal stools.21	C	Evidence-based guidelines, consistent observational evidence