High sensitivity troponin: The Sisyphean pursuit of zero percent miss rate for acute coronary syndrome in the ED

Background: The United States Food and Drug Administration recently approved a high sensitivity troponin (hsTn) assay for use. Recent literature has investigated the diagnostic accuracy of hsTn for acute coronary syndrome (ACS) in the emergency department (ED) and its use in accelerated diagnostic protocols. Objective: This article evaluates the existing literature and discusses incorporation of hsTn testing into ED clinical practice based on best available evidence. Discussion: Interpretation of this literature for clinical application is challenging due to heterogeneity across studies with regards to the hsTn assays examined, time intervals for delta troponin tests, and study populations. The high sensitivity of these assays is predicated upon the ability of the physician to clinically determine a patient to have a low pre-test probability of disease. Physicians may further ensure maximal sensitivity by defining the cut-off for a positive value as the limit of detection and utilizing delta troponin testing. These assays do not obviate the need to consider follow-up for risk stratification for discharged patients. Higher sensitivity compared to standard troponin tests comes at the expense of lower specificity. Indiscriminate testing may translate to greater numbers of abnormal troponin results in patients with non-ACS syndromes, potentially leading to increased healthcare costs, hospital admissions, increased ED lengths of stay, and unnecessary interventions. Conclusion: As hsTn becomes more widespread, it is imperative emergency physicians understand its potential and limitations. Knowledge of test characteristics is vital to ensure appropriate use. Further study of hsTn is required to optimize use.