title: Evaluation of an improved immunoturbidimetic assay for serum C-reactive protein on a COBAS INTEGRA 400 Analyzer.
abstract: Recent studies have shown that C-reactive protein (CRP) can be used as a prognostic risk marker of cardiovascular disease. This new clinical indication requires accurate and precise measurement of CRP at low concentrations (<5 mg/L). We evaluated the analytical performance of an improved CRP immunoturbidimetric method (CRPLX from Roche Diagnostics) on a COBAS INTEGRA 400 analyzer. The assay is simple and rapid to perform with low sample volume (2.5 microl). The limit of detection is 0.26 mg/L, with a working range extending to 194 mg/l. The method shows low imprecision in the whole dynamic range, with a day-to-day coefficient of variation of 10% at a CRP concentration of 0.66 mg/L. There is no interference by bilirubin, hemoglobin, triglycerides and rheumatoid factor up to high concentrations. It compares well with a high sensitivity nephelometric assay, widely used as reference method, and with a classical turbidimetric assay. We conclude that this CRP assay offers to the clinical laboratory an efficient and reliable alternative tohigh sensitivity immunoassays in the new CRP applications.
authors.affiliation: Laboratorio de Bioquímica, Hospital de Txagorritxu, Vitoria, Spain.
authors.forename: Angela
authors.initials: A
authors.lastname: Sánchez
authors.forename: José L
authors.initials: JL
authors.lastname: Mirabel
authors.forename: Eva
authors.initials: E
authors.lastname: Barrenechea
authors.forename: Josefina
authors.initials: J
authors.lastname: Eugui
authors.forename: Ana
authors.initials: A
authors.lastname: Puelles
authors.forename: Angel
authors.initials: A
authors.lastname: Castañeda
mesh_terms: D001322:Autoanalysis / Q000295:instrumentation; D015415:Biomarkers; D002097:C-Reactive Protein / Q000032:analysis*; D002138:Calibration; D002318:Cardiovascular Diseases / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D009391:Nephelometry and Turbidimetry / Q000379:methods; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein