To properly triage and treat patients with chest pain, it is necessary to provide an early objective diagnosis of infarction within 4 to 4 hours of onset of symptoms. This need is fueled by the necessity to administer thrombolytic therapy within 6 to 8 hours of onset of infarction, together with the need to be more cost effective in screening patients with chest pain that require admission to the hospital. Results of a large trial performed in 11,000 patients with chest pain showed MB CK Subforms reliably excludes or confirms myocardial infarction in the first 6 hours of onset of symptoms, A more recent multi-centered double blind trial confirmed the sensitivity and specifity of MB CK Subforms for early diagnosis, Furthermore, MB CK Subforms correctly diagnosed all the individuals with MI in the first hour of presentation into the emergency room.