A novel sol particle immunoassay for fecal calprotectin in inflammatory bowel disease patients.

Abstract Background We introduce a new assay method to measure the concentration of fecal calprotectinthat can be applied in exclusive analyzers. The assay method uses gold colloidal reagents. In addition, we report performance evaluation results for the new method and the results of comparisons with enzyme-linked immunosorbent assay (ELISA) methods. Methods We evaluated the new method by linearity tests and within-run tests. In addition, we collected specimens from patients with a definitive diagnosis of inflammatory bowel disease ( n = 566) and examined them using the new method. The results were compared with those from 2 commercially available ELISA kits. Results In the linearity tests, the correlation coefficients between the measured values and the theoretical values were 0.9980–0.9990. In the within-run tests, the CVs were 3.4–4.3%. The correlation coefficients for our method and the 2 ELISA kits showed high correlations of 0.945 and 0.942. Conclusions Our assay is capable of measuring calprotectinconcentrations in feces, and has a similar performance to commercially available ELISA methods. Our method is an automated assay system, which is an easier, cheaper, and quicker measurement method than conventional ELISA kits. Therefore, our assay is suitable for daily clinical use.