Evaluation of high-sensitivity assays for cardiac troponin.

Despite the facts that cardiac troponin was introduced 2 decades ago and has been established since 2000 as the preferred biomarker for the diagnosis of myocardial infarction (MI) (1 ), the clinical application of cardiac troponin assays continues to evolve substantively. In large part, this evolution has been driven by sustained progress in the analytical performance of commercially available cardiac troponin assays. Because of improved precision at low cardiac troponin concentrations and data establishing the prognostic relevance of quantitatively minor increases in this biomarker, the clinical decision limit for cardiac troponin has been pushed progressively lower. A recently emerged new generation of research assays for cardiac troponin now has reduced the limit of detection by another 10to 100-fold compared with current commercially available assays (2, 3 ). In this issue of Clinical Chemistry, the report by Eggers et al. (4 ) and 2 reports by Wu et al. (5, 6 ) provide valuable insights into possible new applications for more sensitive assays, as well as raise new questions that must be addressed in the course of evaluation of a new generation of high-sensitivity cardiac troponin assays.