Diagnostic Accuracy of a High-Sensitivity Cardiac Troponin Assay with a Single Serum Test in the Emergency Department.

Body, Richard, Twerenbold, Raphael, Austin, Catrin, Boeddinghaus, Jasper, Almashali, Malak, Nestelberger, Thomas, Morris, Niall, Badertscher, Patrick, McDowell, Garry, Wildi, Karin, Moss, Phil, Gimenez, Maria Rubini, Jarman, Heather, Bigler, Nina, Einemann, Rachael, Koechlin, Luca, Pourmahram, Ghazaleh, Todd, John, Mueller, Christian and Freemont, Anthony (2019) Diagnostic Accuracy of a High-Sensitivity Cardiac Troponin Assay with a Single Serum Test in the Emergency Department. Clinical Chemistry, 65 (7). ISSN 0009-9147

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Abstract

OBJECTIVES:We sought to evaluate diagnostic accuracy of a high-sensitivity cardiac troponin I (hs-cTnI) assay for acute coronary syndromes (ACS) in the emergency department (ED). The assay has high precision at low concentrations and can detect cTnI in 96.8% of healthy individuals. METHODS:In successive prospective multicenter studies ("testing" and "validation"), we included ED patients with suspected ACS. We drew blood for hs-cTnI [Singulex Clarity® cTnI; 99th percentile, 8.67 ng/L; limit of detection (LoD), 0.08 ng/L] on arrival. Patients also underwent hs-cTnT (Roche Elecsys) testing over ≥3h.The primary outcome was an adjudicated diagnosis of ACS, defined as acute myocardial infarction (AMI; prevalent or incident), death, or revascularization within 30 days. RESULTS:The testing and validation studies included 665 and 2470 patients, respectively, of which 94 (14.1%) and 565 (22.9%) had ACS. At a 1.5-ng/L cutoff, hs-cTnI had good sensitivity for AMI in both studies (98.7% and 98.1%, respectively) and would have "ruled out" 40.1% and 48.9% patients. However, sensitivity was lower for ACS (95.7% and 90.6%, respectively). At a 0.8-ng/L cutoff, sensitivity for ACS was higher (97.5% and 97.9%, ruling out 28.6% patients in each cohort). The hs-cTnT assay had similar performance at the LoD (24.6% ruled out; 97.2% sensitivity for ACS). CONCLUSIONS:The hs-cTnI assay could immediately rule out AMI in 40% of patients and ACS in >25%, with similar accuracy to hs-cTnT at the LoD. Because of its high precision at low concentrations, this hs-cTnI assay has favorable characteristics for this clinical application.