Fecal Calprotectin in Nosocomial Diarrhea: A Prospective Observational Study

Objective: Fecal calprotectin (FC) has an essential role in differentiating inflammatory diarrhea from functional diarrhea in an outpatient setting; however, its role in nosocomial diarrhea remains not well explored. Materials and Methods: This is a prospective observational study. We included adult inpatients with nosocomial diarrhea and categorized them into diarrhea likely (group A) and unlikely (group B) to have lesions in the colonic mucosa. Group A included infectious diarrhea such as Clostridium difficile and ischemic colitis. Group B comprised tube-feeding diarrhea, non-C. difficile antibiotic-associated diarrhea, and drug-induced diarrhea. The FC levels were compared between the two groups. Results: 135 patients were included, 45 in group A and 90 in group B. Median FC was 902 mg/kg (interquartile range [IQR] 549-2,175) of feces in group A, significantly higher than the median level of 377 mg/kg (IQR 141-664) of feces in group B (p<0.001). The area under the receiver operating characteristic curve was 0.798 (95% confidence interval: 0.717-0.879). At the standard cutoff of 50 mg/kg of feces, the sensitivity and specificity were 97.8% and 7.8%, respectively. Conclusion: FC was significantly higher in nosocomial diarrhea likely to have mucosal lesions; however, its clinical usefulness was limited due to poor specificity. Trial registration: The trial was registered at ClinicalTrials.gov. (reg. no. NCT04491799. Registered on 26/04/2020).