This prospective, multicenter study involving unselected patients examined the diagnostic performance of new, sensitive cardiac troponin assays for the early diagnosis of acute myocardial infarction at the time of the patient’s presentation to the emergency department. We report four major findings with the potential to improve the ability both to rule in and to rule out acute myocardial infarction. First, the diagnostic accuracy of the four sensitive cardiac troponin assays was already very high at presentation. The AUCs ranged from 0.94 to 0.96. The diagnostic performance of cardiac troponin levels observed in this study is even superior to the accuracy of B-type natriuretic peptides in the diagnosis of heart failure