Blood testing for biomarkers of myocardial injury plays an increasingly important role for the evaluation, diagnosis, and triage of patients with chest pain. The guidelines for the diagnosis of myocardial infarction (MI) have recently changed and prominently incorporate the results of cardiac marker testing in the clinical definition of MI. We review these updated guidelines for MI definition as it pertains to cardiac biomarker testing and further compare the differing biology and release kinetics of clinically relevant biomarkers. Finally, we define the contemporary use of cardiac biomarker testing for patients with chest pain, including appropriate integration of point-of-care testing into day-to-day clinical use.