Emergency Department Multimarker Point-of-care Testing Reduces Time to Cardiac Marker Results Without Loss of Diagnostic Accuracy

We assessed the hypothesis that emergency department point-of-care (POC) testing for myoglobin and cardiac troponin T (cTnT) reduces the time to result with no reduction in diagnostic accuracy for acute coronary syndrome (ACS) compared with standard-of-care local laboratory (LL) tests for creatine kinase-MB (CK-MB) and cTnT. We prospectively compared POC quantitative myoglobin and cTnT with LL results for CK-MB and cTnT in 223 emergency department patients with suspected ACS but no ST-segment elevation. Testing was done at baseline, 3, 6, 12, and 24 hours. Those considered ACS positive had one or more of the following: discharge diagnosis of acute myocardial infarction or unstable angina, positive catheterization, received percutaneous coronary intervention or coronary artery bypass graft, death, or recurrent myocardial infarction during 30-day follow-up. The time from presentation to baseline marker result was compared using paired-sample t test. Diagnostic accuracy was assessed using sensitivity and specificity with associated 95% confidence intervals. Fifty-six patients (25.1%) were ACS positive. Mean ± SD time to baseline results for POC was 2.1 ± 1.4 hours, whereas LL was significantly longer (2.5 ± 1.8 hours, P < 0.01). For baseline, the sensitivity and specificity of POC for ACS were 30% and 91%, respectively, whereas LL was 30% and 92%. When serial blood draws were considered, the sensitivity and specificity were 43% and 88% for POC, and 43% and 91% for LL. Point-of-care testing decreases the time to obtain baseline cardiac markers compared with LL testing; it may be possible to start treatment earlier with POC.