A-085 Analytical Performance of BÜHLMANN sCAL® turbo, a New, Reliable and Precise High-Throughput Assay to Assess the Inflammatory Status of Patients

Abstract

Abstract Background Serum calprotectin plays an important pro-inflammatory role in the innate immune system and is a promising marker with several potential applications in rheumatoid arthritis, juvenile idiopathic arthritis and systemic onset juvenile idiopathic arthritis. Serum calprotectin can be a useful tool to monitor disease activity and predict treatment response in these patients. Methods The aim of this work was to evaluate the analytical performance of BÜHLMANN sCAL® turbo, a new turbidimetric test on clinical chemistry analyzers for the determination of calprotectin levels in serum. Assay characteristics were established according to CLSI guidelines (CLSI C28-A3, EP05-A3, EP07-A3, and EP09-A3). 111 samples were measured using 3 lots over 3 days and compared to another commercially available assay. Results The analytical measuring range from 0.23 to 15 µg/mL, extended to 225 µg/mL with an additional dilution in an automated rerun on a clinical chemistry analyzer, is suitable to address the described pathologies. 160 self-declared healthy adults (m/w) aged 18–83 years exhibit reference limits of 1.77 and 1.10 µg/mL when sampled either in a native tube or a gel separator tube and processed within 3.4 h after collection, respectively. With a within-laboratory precision up to 5.1% and a reproducibility up to 11.1% the method is precise, reliable and suitable for routine use. Tested concentrations of oral and injectable pharmaceuticals showed no interference. Hemolyzed samples are not recommended. It shows good comparison to an existing commercial assay with a bias of 12.5% (Bland-Altman) and a slope of 1.16 (Passing-Bablok). Conclusion A high-throughput test on clinical chemistry analyzers is now available with the turbidimetric BÜHLMANN sCAL® turbo allowing reliable and precise measurements of serum calprotectin levels.