Single High-Sensitivity Point of Care Whole Blood Cardiac Troponin I Measurement to Rule Out Acute Myocardial Infarction at Low Risk.

<bold>Background: </bold>High-sensitivity cardiac troponin (hs-cTn) laboratory assays are used to rule out myocardial infarction (MI) on presentation, but prolonged result turn-around times can delay patient management. Our primary aim was to identify patients at low risk of index MI using a rapid, point of care (POC), whole blood hs-cTnI assay at presentation, with potential early patient discharge.<bold>Methods: </bold>Consecutive emergency department patients from two prospective, observational studies with suspected acute coronary syndrome were enrolled. A POC hs-cTnI assay (Atellica® VTLi) threshold using whole blood at presentation, that resulted in a negative predictive value (NPV) of ≥99.5% and sensitivity of ≥99% for index MI, was derived (Safe Emergency department dIscharGE rate [SEIGE]) and validated using plasma (Suspected acute myocardial infarction in Emergency [SAMIE]). Event adjudications were established using hs-cTnI assay results from routine clinical care. The primary outcome was MI at 30-days.<bold>Results: </bold>1086 patients (8.1% MI) were enrolled in a US derivation cohort (SEIGE) and 1486 (5.5% MI) in an Australian validation cohort (SAMIE). A derivation whole blood POC hs-cTnI concentration of <4ng/L provided a sensitivity of 98.9% (93.8-100%) and NPV of 99.5% (95% CI: 97.2-100%) for ruling out MI. In the validation cohort, sensitivity was 98.8% (93.3-100%) and NPV was 99.8% (99.1-100%). 17.8% and 41.8%, respectively, were defined as low risk for discharge. 30-day adverse cardiac events were 0.1% (n=1) for SEIGE and 0.8% (n=5) for SAMIE.<bold>Conclusions: </bold>A point-of-care, whole blood hs-cTnI assay permits an accessible, rapid and safe exclusion of MI, and may expedite discharge from the emergency department. [ABSTRACT FROM AUTHOR]