The current study has several limitations. First, we evaluated four sensitive cardiac troponin as-says. We hypothesize that our findings can be generalized to other cardiac troponin assays that have similar sensitivity and precision. However, additional large, multicenter studies are needed to confirm this hypothesis. Second, since this was a prospective, observational study, we cannot quantify the clinical effect associated with the increase in early diagnostic accuracy. Intervention studies are warranted to provide this important additional information.Third, our study showed a high diagnostic accuracy of sensitive cardiac troponin assays among patients with impaired renal function; however, we cannot comment on the accuracy among patients with terminal kidney failure requiring dialysis, since such patients were excluded from our study. Fourth, some of the patients with positive results of sensitive cardiac troponin assays whose final diagnosis was classified as a condition other than an acute myocardial infarction might have had small acute myocardial infarctions that were below the limit of detection of the conventional assays, a result that might have led to an underestimate of the specificity of the sensitive assays. In conclusion, sensitive cardiac troponin assays have an excellent diagnostic performance as early as at the time of a patient’s presentation in the emergency department and may thereby substantially improve the early diagnosis of acute myocardial infarction, particularly in patients with a recent onset of chest pain.