Cardiac troponin (cT) is released after myocardial damage. In the appropriate clinical setting, a measured elevation of cT can increase the diagnostic rate of myocardial infarction and acute coronary syndrome. Elevations of cT, however, can occur in a wide variety of other clinical situations. Failure to recognize this can lead to an over-diagnosis of myocardial infarction (MI). We present clinical cases from our institution that illustrate this diagnostic problem, and review similar cases in the literature. We also discuss the implications of an erroneous diagnosis of myocardial infarction, for the patient and for the health services.