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.