High-Sensitivity Cardiac Troponins in the Emergency Department: Transforming Acute Coronary Syndrome Diagnosis

Recent advances in emergency department (ED) assessment of suspected acute coronary syndrome (ACS) have been driven by the use of high-sensitivity cardiac troponin (hs-cTn) assays, which allow detection of myocardial injury at levels below the analytical detection limit of traditional cardiac troponin assays, and facilitate rapid diagnostic pathways. The value of these is, however, not to be judged based on the concentration of the biomarkers alone, but integrated with symptoms, electrocardiography (ECG), time of presentation, assay-specific thresholds, and serial change. This narrative review brings together literature provided by the authors regarding the evolution of hs-cTn assays, single-sample vs serial testing, point-of-care testing, sex-related differences, chronic kidney disease (CKD), hemodialysis, coronary CT angiography (CCTA), and risk stratification. We propose a pragmatic conceptual model in which hs-cTn helps with the rule-out, rule-in and observation decision-making process, but is not used as a standalone diagnosis of type 1 myocardial infarction (MI). Specific focus is placed on analytical and clinical constraints such as non-ACS elevations, inter-assay non-interchangeability, and uncertain generalizability of pathways to populations. Future directions include, but are not limited to, personalized interpretations, evidence-based incorporation of biomarker and anatomical imaging (with the support of artificial intelligence (AI) tools). Overall, it is concluded that when used as part of a structured clinical pathway, hs-cTn enhances the efficiency and sensitivity of diagnosis and should not be used in place of clinical reasoning or evidence of myocardial ischemia.