Abstract Background Fecal calprotectin (FC) is a widely used biomarker for monitoring disease activity in inflammatory bowel disease (IBD). While immunoassay technique is a reliable method and is commonly used in clinical laboratories, a newer technique, the latex agglutination reaction and chemiluminescent Immunoassay, offer automated stool processing at a lower cost but remained unvalidated. This study aimed to evaluate the correlation and diagnostic performance of different techniques against endoscopic outcomes. Methods A prospective cohort study was conducted from August 2023 to January 2025, enrolling adult IBD patients who underwent colonoscopy. Stool samples were collected one day prior to the procedure and analyzed for calprotectin using three techniques, OC-SENSOR Ceres (EIKEN Chemical Co.,LTD, Tokyo, Japan) and EliA Calprotectin 2 (Fluoroenzymeimmunoassay, Thermo Fisher Scientific, Sweden), and Liaison Calprotectin (Chemiluminescent Immunoassay, DiaSorin, Italy). The correlation and diagnostic performance of all techniques were evaluated against the Mayo Endoscopic Score (MES) for ulcerative colitis (UC) and Simple Endoscopic Score for Crohn’s disease (SES-CD) for Crohn’s disease (CD). Mucosal healing was defined by MES ≤1 or SES-CD 3. Results There were 133 participants (74 UC, 59 CD) enrolled in this study. All three FC assays demonstrated strong correlations with each other. OC-SENSOR showed strong correlation with EliA (Spearman r = 0.96, P0.01) and Liaison (r = 0.95, P0.01). Similarly, EliA and Liaison were highly correlated (r = 0.95, P0.01). In UC, the correlation coefficients with MES were r = 0.49 for OC-SENSOR, 0.54 for EliA, and 0.48 for Liaison, while the correlations with SES-CD were 0.67 for OC-SENSOR, 0.67 for EliA, and 0.65 for Liaison, all statistically significant (P0.01). Mucosal healing was observed in 75 participants (56.4%), including 46 UC and 29 CD. The FC measurements of all techniques stratified by endoscopic severity were demonstrated in Table 1. As shown in Figure 1, the AUROC values were comparable among the three assays, with OC-SENSOR at 0.83, EliA at 0.83, and Liaison at 0.82. The AUROCs for predicting mucosal healing in UC were 0.78, 0.80, and 0.78 for OC-SENSOR, EliA, and Liaison respectively, while in CD, they were 0.90, 0.87, and 0.89, respectively. Conclusion FC is a reliable tool for assessing endoscopic mucosal inflammation in IBD. All measurement techniques had strong correlation and similar diagnostic performance. However, absolute values differ across assays, therefore should not be interchanged when monitoring the same patient. Conflict of interest: Dr. Chaemsupaphan, Thanaboon: No conflict of interest Salaemae, Marianee: No conflict of interest Sattayalertyanyong, Onuma: No conflict of interest Limsrivilai, Julajak: No conflict of interest
Chaemsupaphan et al. (Thu,) studied this question.