Optimal positioning of biomarkers according to ulcerative colitis activity

The diagnostic performance and clinical utility of fecal calprotectin (FC), fecal immunochemical occult blood test (FIT), leucine-rich alpha-2 glycoprotein (LRG), C-reactive protein (CRP), and prostaglandin E-major urinary metabolite (PGE-MUM) as established biomarkers for ulcerative colitis (UC) were evaluated. Significant correlations were observed between the clinical activity index, Mayo endoscopic subscore (MES), and each biomarker. Among MES groups, fecal biomarkers demonstrated significant differences, except between MES 2 and MES 3. CRP and LRG showed significant differences, except between MES 1 and MES 2. PGE-MUM exhibited significant differences across all MES groups. Areas under the curve (AUCs) for receiver operating characteristic (ROC) analysis in predicting MES 0 or 1 were as follows: FC, 0.891; FIT, 0.853; LRG, 0.723; CRP, 0.747; PGE-MUM, 0.795. For predicting MES 0 alone, AUCs were as follows: FC, 0.885; FIT, 0.845; LRG, 0.708; CRP, 0.691; PGE-MUM, 0.732. In distinguishing between each MES group, fecal biomarkers exhibited the highest AUC and accuracy in differentiating MES 0 from MES 1, whereas LRG, CRP, and PGE-MUM were most effective in differentiating MES 2 from MES 3. In summary, in UC, fecal biomarkers effectively detect mucosal healing, whereas LRG, CRP, and PGE-MUM are valuable for assessing mucosal healing and active inflammation.