With its superior sensitivity and specificity, cardiac troponin has gradually replaced other cardiac enzymes, and is now the biomarker of choice in making the critical diagnosis of an acute coronary syndrome (ACS). The early stratification of risk from unstable angina to non-ST segment elevation myocardial infarction (NSTEMI), is crucial in the timing and treatment of the ACS. Troponin elevations have also been shown to be powerfully prognostic in a variety of clinical settings and because of this predictive value, may be useful in determining benefit of various clinical interventions. However, inherent in this improved sensitivity and specificity of the measurement tools is the inclusion of non-ACS patients with abnormal troponin measurements. Increased understanding of the alternative diagnoses associated with elevated troponins as well as assays which allow more rapid and accurate diagnosis of ACS, are needed to further improve patient care. Clinical trials of risk stratification controlling for concomitant associated diagnoses including renal insufficiency, pulmonary embolism, atrial fibrillation and congestive heart failure will provide data to optimize this tool.