This study was undertaken to evaluate the diagnostic accuracy and practicality of Emergency Department (ED) testing for cardiac biomarkers in the diagnosis of acute coronary syndromes. All patients presenting with chest pain to the ED of a community-based tertiary care facility over a 16-day period (N = 205) had blood drawn and tested for cardiac troponin I, myoglobin, and CK-MB by a quantitative, point-of-care instrument system (Stratus CS). Point-of-care cardiac testing expedited diagnosis by decreasing the turn-around time by 55% compared to the central laboratory. The extreme sensitivity of the cardiac troponin I assay integral to this system was responsible for the high diagnostic accuracy (100% sensitivity; virtually 100% specificity, compared with the final assigned diagnosis). The assay also identified a clinically significant "high-risk" zone for near-future cardiac events: 17 patients were identified and four of these progressed to further cardiac events in the next 9 months. Further studies to explore the clinical implications of this high-risk zone are warranted.