Measurement of cardiac troponins (cTnT and cTnI), the only cardiac specific biomarkers available, is the gold standard in diagnosing acute coronary syndrome. Due to the recent introduction of more sensitive methods i.e. the high-sensitivity troponin assays, the diagnostic cut-off concentrations have very recently been established. We describe two male patients who presented at the emergency department with acute chest pain, but in whom clear evidence for a myocardial infarction in the ST segment of the EKG was lacking. Case 1 illustrates that such assays enable the earlier diagnosis of acute myocardial infarction. Case 2 shows that the diagnosis of acute myocardial infarction should be accompanied by a typical rise or fall of troponin concentrations. The latest insights into high-sensitivity cardiac troponin assays are discussed in this article. We focus specifically on sensitivity and specificity, reference values obtained from a healthy control group, and the reference change value required to detect acute myocardial infarction.