RT Journal Article SR Electronic T1 Understanding cardiac troponin part 2: early rule out of acute coronary syndrome JF Emergency Medicine Journal JO Emerg Med J FD BMJ Publishing Group Ltd and the British Association for Accident & Emergency Medicine SP 192 OP 197 DO 10.1136/emermed-2017-207161 VO 35 IS 3 A1 Edward Carlton A1 Richard Body YR 2018 UL http://emj.bmj.com/content/35/3/192.abstract AB Chest pain of suspected cardiac origin is a very common emergency department presentation. Over the past decade, there has been an exponential growth in strategies that promote blood sampling at earlier and earlier time points after presentation to facilitate the rule out of acute coronary syndrome.In part 2 of this series, we examine key concepts from the recent literature with the aim of improving clinicians’ understanding of the rule-out strategies available to them and provide a structured overview of strategies that facilitate discharge with blood testing over <3 hours.