Highly Sensitive Troponin Assays and the Cardiology Community: A Love/Hate Relationship?

The development of highly sensitive assays for cardiac troponin T (hs-cTnT)4 and cardiac troponin I (hs-cTnI) represents the latest technological advance in a field that has witnessed continual progression toward more sensitive andmore precise tools for detecting car-diac injury. The hs-cTnT assay, for example, can detect cTnT concentrations 10-fold lower than the current fourth-generation assay, with high precision at the myocardial infarction (MI) detection limit. Despite the potential for such evolution to improve patient care, clinicians, including practicing cardiologists, often find themselves poorly prepared for the introduction of more-sensitive assays, because they fail to consider the implications of increasing sensitivity on the interpreta-tion of the test results. We believe that highly sensitive troponin assays offer new opportunities to improve cardiovascular health, but they also present challenges in the areas in which troponin testing is most com-monly used today. Terminology Although it may seem natural to use the terminology “high-sensitivity troponin T (hs-cTnT) or troponin I (hs-cTnI) ” in a manner similar to high-sensitivity C-reactive protein (hs-CRP), we discourage this ap-proach and strongly recommend that “highly sensi-tive ” or “sensitive ” be used to describe the assay only and not the biomarker. The highly sensitive assays measure the same protein as the standard assays, and cardiac troponin assays that are even more sensitive assays will certainly be developed, thus making any “high sensitivity ” designation obsolete. NewOpportunities and Indications for Troponin Testing The ability to detect concentrations of circulating tro-ponin in the single-digit nanogram-per-liter range has expanded the potential applications of troponin testing in new directions, including in the ambulatory setting. For example, using research versions of the hs-cTnT assay, investigators from the Valsartan Heart Failur