Many professional societies publish acute intervention guidelines, and most are predicated on the knowledge of an accurate diagnosis. In the emergency department patients do not arrive with a diagnosis, rather they present with symptoms that must be evaluated in the context of their estimated illness severity. Unique to emergency medicine practice, and within a relatively short time frame, all emergency patients must go somewhere else. Appropriate dispositions may be home, admission to a chest pain center, hospitalization to a regular medical floor, or transfer to an intensive care unit, but they cannot stay in the emergency department. This disposition process must occur, even in the setting of great diagnostic uncertainty. Since an accurate diagnosis is a time dependent event, requiring data collection and analysis, emergency department disposition decisions may be based on risk estimates rather than an established diagnosis. Owing to the subjective nature of the early evaluation process, biomarkers currently determine much of the risk stratification process. In this manuscript, we discuss the value of biomarkers as an adjunct to the diagnosis and risk stratification process for patients presenting to the emergency department with suspected acute coronary syndromes and acute heart failure.