Calprest ELISA vs. Liaison® Chemiluminescence: Evaluating Accuracy, Efficiency, and Clinical Utility in Fecal Calprotectin Testing.

Background: Ulcerative colitis (UC) management relies on accurately assessing disease activity. Fecal calprotectin (FC) is a promising non-invasive biomarker, but method-specific differences in measurement can affect interpretation. Objective: To compare the performance of Calprest ELISA and DiaSorin Liaison CLIA in measuring FC concentrations and their correlation with endoscopic findings in UC. Methods: Stool samples from 40 UC patients were analyzed using both methods, with 138 samples collected across three clinical timepoints. Spearman's correlation, Wilcoxon test, Bland-Altman analysis, and ROC curves were used to evaluate method agreement and diagnostic performance relative to Mayo endoscopic scores. Results: A total of 135 paired results showed strong correlation (ρ = 0.795, p < 0.001) but significant inter-method differences (p = 0.039). Liaison tended to yield higher FC values. ROC analysis established optimal cut-offs for detecting endoscopic remission and active disease: 47.95/69.55 µg/g (Liaison) and 65/125 µg/g (Calprest). Calprest demonstrated slightly better diagnostic accuracy. Conclusions: Both methods are reliable for monitoring UC activity. Calprest offers greater dynamic range, while Liaison excels in automation and speed. Method-specific thresholds should guide clinical interpretation to ensure accurate disease monitoring.