Few, if any, studies have evaluated the rule-out (R/O) of non-ST-segment elevation (NSTE) ACS which requires the sensitivity and negative predictive value (NPV) of the test to approach 100%. An alternative triage approach, utilizing a portable magnetocardiography (MCG) instrument in the emergency setting, may lead to a more accurate R/O for NSTEMI, UA, and clinically significant non-ACS coronary artery disease (CAD), in patients presenting to the ED with chest pain. MCG in the emergency setting is a new use of this non-invasive technique and may serve as an adjunctive aid that can improve cardiac triage for NSTE ACS and clinically significant CAD.This raises the research question of whether MCG may be useful for the early triage of patients with acute chest pain. In the study protocol, a clinical evaluation is defined that will assess the ability of a portable MCG instrument, using a fixed algorithm, to R/O ACS, with improved safety (i.e. << 2% false negative rate) in patients presenting to an emergency setting with chest pain.