Optimal Detection of Acute Myocardial Injury and Infarction with Cardiac Troponin: Beyond the 99th Percentile, into the High-Sensitivity Era

Purpose of Review Cardiac troponin (cTn) is the biomarker of choice for the diagnosis of acute myocardial infarction (MI); use of this biomarker has centered around the 99th percentile upper reference limit (URL) for healthy populations. Recent development and regulatory approval of high-sensitivity cardiac troponin (hs-cTn) assays have required a fresh look at utilization of the 99th percentile URL. This review covers issues regarding the 99th percentile URL and approaches for use of cTn as biomarker for detecting cardiac injury and diagnosis of acute myocardial infarction. Recent Findings Development of hs-cTn assays has allowed determination and use of sex-specific 99th percentile URLs for assessing cardiac injury and increased the utility of cTn values below the 99th percentile URL. This improved analytical performance for hs-cTn assays has allowed for development of accelerated diagnostic protocols (ADPs) for rapid assessment and disposition of patients based on serial sampling of cTn for use in acute MI diagnosis as soon as 0-1 h after clinical presentation. The 99th percentile URLs of cTn is essential for detecting cardiac injury; however, use of the 99th percentile URLs in the era of hs-cTn results may be modified. ADPs have the potential to substantially decrease the time many patients spend under evaluation for acute MI, thereby potentiating improvement in patient satisfaction, decreased healthcare costs, and reducing the burden on emergency departments.