A new study published in JAMA evaluated the performance of a cardiac troponin I threshold of 5 ng L at presentation as a risk stratification tool in patients with suspected acute coronary syndrome. This systematic review searched MEDLINE EMBASE Cochrane and Web of Science databases from January 1 2006 to March 18 2017. The findings revealed that among 22 8239 457 patients included the primary outcome myocardial infarction or cardiac death at 30 days occurred in 12.4 . Cardiac troponin I concentrations were less than 5 ng L at presentation in 49 patients in whom there were 60 missed index or 30 day events 59 index myocardial infarctions 1 myocardial infarction at 30 days and no cardiac deaths at 30 days . Moreover there were no cardiac deaths at 30 days and 0.1 at 1 year. Hence it was inferred that among patients with suspected acute coronary syndrome a high sensitivity cardiac troponin I concentration less than 5 ng L identified those at low risk of myocardial infarction or cardiac death within 30 days. It was stated that further research is necessary in order to understand the clinical utility and cost effectiveness of this approach to risk stratification.