(Level of Evidence: C) The majority of patients presenting to the ED with chest pain do not have ACS (Figure 1), and most are at low risk for major morbidity and mortality.35 Low-risk patients are usually identi- fied by an absence of history of cardiovascular disease, normal or near-normal initial ECG, normal initial troponin, and clinical The utility of an accelerated diagnostic protocol for detecting patients with benign conditions versus those who require admission for serious disease has been established.35 At minimum, these protocols involve serial ECGs and troponin measurements, both of which can be performed in the ED, a separate chest pain unit, or a telemetry unit. A 30-day negative predictive value >99% for ACS has been reported for patients presenting to the ED with chest pain who undergo a 2-hour accel- erated diagnostic protocol composed of a TIMI risk score of 0, normal ECG, and normal high-sensitivity troponin at 0 hours and 2 hours (assuming appropriate follow-up care).65,210 Some pro- tocols also call for a functional or anatomic test (eg, treadmill test, rest scintigraphy, coronary CT angiography, stress imaging). Coronary CT angiography is associated with rapid assessment, high negative predictive value, decreased length of stay, and ; however, in the latter studies, it increased the rate of invasive coronary angiography and revascularization with uncertain long-term benefits in low-risk patients without ECG or Accelerated diagnostic protocols are also potentially applicable in intermediate-risk patients, whose pre- sentation includes a history of cardiovascular disease, diabetes mellitus, chronic kidney disease (CKD), and/or advanced age.202 See Online Data Supplement 8 for additional information on discharge from the ED or chest pain unit. 4. 