Rapid rule-out of acute myocardial infarction at the emergency department with A troponin point of care testing in the COVID-19 era

INTRODUCTION: Emergency department (ED) investigations are time-consuming, mainly because of the turnaround time of laboratory assays. Furthermore, several reports showed that more extended emergency stays during the COVID-19 pandemic increase the likelihood of cross-infection. The introduction of troponin point of care assays with improved analytical precision and rapid availability of results compared to central laboratory testing reduces decision-making time in the ED to rule out AMI. OBJECTIVE: We aimed to compare the diagnostic performance of a troponin I POCT assay with a 10-minute turnaround time and the high sensitivity cardiac troponin (hs-cTn) performed in the laboratory. METHOD: A single-center observational cohort study carried out in adults’ patients presenting with non-traumatic chest pain suggestive of AMI at the ED of a tertiary hospital from Jul 29 to Sept 29, 2020. Troponin concentrations were measured on ED arrival and three (3) hours later with both a POCT assay (i-STAT CTnI; Abbott POC) and laboratory hs-cTnI assay (Architect hs-cTnI c8000). RESULTS: On admission and after 3 hours, both POCT and lab Hs-CTn showed the same sensitivity for diagnosing NSTEMI which was 93.8% and reached 100%. The negative predictive value (NPV) for POC CTnI was significantly higher than that for Lab Hs-Tn at 0 h (96.4% versus 95%). After 3 hours, both POCT and Lab Hs-Tn showed a NPV of 100%. Both assays showed higher AUC at 0 hour (POC TnI: 0.972 vs. lab Hs-Tn: 0.957). At 3 hour, the AUC for POC TnI was 0.996 and Lab Hs-Tn AUC was 0.998. (Fig. 1) The average length of hospital stay was 200 min for POCT vs. 464 min for hs-Lab (P < 0.001). CONCLUSION: The results our preliminary cohort suggest that in chest pain patients, the sensitivity of POC CTnI on admission and 3 hours later was comparable to that of the central lab hs-CTnI for ruling in and ruling out NSTEMI. Furthermore, after 3 hours of presenting to the ED, chest pain is not likely due to NSTEMI in patients with a negative POC CTnI assay. Therefore, patients could be safely discharged from the ED with a short emergency stay.