Evaluation of Hitachi 7600-110(R) for Quantitative Analysis of C-Reactive Protein

Chang, Cheol Wung; Lee, You Kyoung; Choi, Tae Youn; Lee, Dong Wha

Abstract

BACKGROUND: The C-reactive protein(CRP) is one of the "acute phase" proteins and it is known to be the most sensitive indicator of the inflammatory and/or necrotic process. Traditional methods for measuring CRP are capillary precipitation assay and latex agglutination assay. However, these methods have low sensitivity and provide only qualitative results. Recently the development of specific and very sensitive assays for CRP using highly specific monoclonal antibodies for CRP have done, including radioimmunoassay, nephelometric assay(NA), and turbidimetric immunoassay(TIA). We evaluated the Hitachi 7600-110(R)(Hitachi Co., Japan) using TIA in the measurement of CRP and compared its results to those of the the LX-M(R)(Eiken Chemical Co., Japan) using NA in order to replace the Hitachi 7600-110(R) for quantitative analysis of CRP.
METHODS
CRP were measured by the Hitachi 7600-110(R) using TIA and the LX-M(R) using NA in the sera from 106 patients. The relationship between results of Hitachi 7600-110(R) and LX-M(R). By performing 20 repetitive assays at three levels of CRP control serum and pooled sera, within-run, within-day, and between-day precision of the Hitachi 7600-110(R) were established.
RESULTS
When the CRP value of 4.60 +/- 5.65 mg/dL by the Hitachi 7600-110(R) was compared with that of 3.71 +/- 4.32 mg/dL by the LX-M(R), coefficients of correlation of 0.994 was obtained. The regression equation was Y(Hitachi 7600-110(R)) = 1.298 X(LX-M(R)) - 0.211(r=0.994, n=106). CVs of CRP measured by Hitachi 7600-110(R) were 5.45% at 0.82 mg/dL, 1.32% at 2.39 mg/dL, and 2.37% at 4.62 mg/dL. The precision was excellent in each group. The linearity was acceptable, and sample to sample carry-over was 0.8%.
CONCLUSIONS
The Hitachi 7600-110(R) using TIA, compared with the LX-M(R) using NA, showed good coefficient of correlation and excellent precision. Therefore the Hitachi 7600-110(R) can replace the LX-M for quantitative analysis of CRP.