Comparison of novel and familiar commercial kits for detection of C-reactive protein levels

Abstract

In this study, randomized patient sera were used to simultaneously evaluate an automated C-reactive protein (CRP) assay and a commercial semi-automated microCRP assay with respect to correlation, linearity, and accuracy. Patient specimens were analyzed; two independent assay runs were performed on i-CHROMA (Boditech Med Inc., Korea) and IMMAGE 800 (Beckman Coulter Inc., USA) analyzers to estimate the between- and within-run precision. All systems were calibrated, and quality-control materials were analyzed according to the manufacturer’s instructions. The results using the control materials were within the respective manufacturers’ specified limits. The comparison studies were designed using the CLSI EP9-2A guidelines. The mean serum CRP concentrations were 123.2 ± 123.5 mg/L (95 % confidence of interval (CI) 97.9–148.3) using the CRP assay and 130.1 ± 109.3 mg/L (95 % CI 107.9–152.4) using the microCRP assay. The variance values were σ = 15,252.6 and 11,935.8 for the CRP and microCRP assays, respectively. The concordance correlation coefficient value was calculated as 0.8314 (95 % CI 0.7594–0.8833). There was a significant correlation between the CRP and microCRP assays: r = 0.8392 and 95 % CI 0.7675–0.8902 (p < 0.0001). The CRP and microCRP detection methods were well correlated. The i-CHROMA has many advantages over the IMMAGE 800 with respect to space required, analysis time, and system setup/application costs in a laboratory. It may be an attractive instrument for small and intermediate medical centers.