A New Single-test Rule-out for Acute Myocardial Infarction?

A single 15-minute troponin concentration measurement using a novel point-of-care assay (Tnl-Nx) produced similar results to a lab-based high-sensitivity cardiac troponin assay for the rule-out of acute myocardial infarction (MI), new study results indicate. 

Researchers for the preliminary cohort study included 354 patients presenting to the emergency department with acute MI symptoms. The authors compared the TnI-Nx assay to the hs-cTnl assay using area under receiver operator characteristic curve (AUC) and sensitivity, negative predictive value, and the proportion of negative test results at thresholds with 100% sensitivity. The primary study outcome was type 1 acute MI during index presentation.  

According to the results, there was no difference between the result of the Tnl-Nx assay (AUC=0.975; 95% CI, 0.958 to 0.993) and the hs-cTnl (AUC=0.970; 95% CI, 0.949 to 0.990; P=0.46). A TnI-Nx assay result of < 11 ng/L identified 56.7% of patients as low risk, with a sensitivity of 100% and a negative predictive value of 100%. In comparison, an hs-cTnI assay result of less than 3 ng/L identified 43.5% as low risk, with a sensitivity of 100%. 

The researchers noted in their conclusion that use of this assay in the emergency department “may facilitate earlier decision making and could expedite the safe discharge of a large proportion of low-risk patients.”

Source: JAMA Cardiology