Photo Credit: Marco Marca

Fecal calprotectin (FC) serves as a promising biomarker for evaluating ulcerative colitis (UC) endoscopic activity, yet determining the optimal FC cutoffs for differentiating Mayo endoscopic subscores (MES) remains uncertain. Results of a retrospective analysis of 177 adult patients with UC between January 2017 and March 2023 were published online in Inflammatory Bowel Diseases. Clinical data and FC levels from US-based Werfen Diagnostics were collected within 30 days before colonoscopy or flexible sigmoidoscopy. Three independent inflammatory bowel disease specialists reviewed the most severe endoscopic images to grade MES. Results showed a strong positive correlation between FC and MES (Spearman’s r = 0.709; P < .01) and other clinical parameters. An FC cutoff of 60 mcg/g effectively distinguished MES 0 from MES 1-3 (sensitivity, 0.78; specificity, 0.97; AUC, 0.901) and predicted clinical remission (sensitivity, 0.83; specificity, 0.98; AUC, 0.921). FC cutoffs of 110 mcg/g and 310 mcg/g effectively differentiated MES 0-1 from MES 2-3 and MES 0-2 from MES 3, respectively. These findings underscore the utility of FC in assessing endoscopic inflammation, especially in distinguishing MES 0 from MES 1-3. Sensitivity analysis confirmed robust results.