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Improvements in cardiac troponin (cTn) assays have outstripped the ability of clinicians to keep up with how to use them clinically. Marketing efforts and the lack of adequate quality control by some journals have made this situation still more difficult. Only recently have our professional organisations begun to provide educational guidance. This articulation will be practical. Most principles applicable to high sensitivity assays are the same as those for present assays, but comments at the end of each section will discuss them specifically. It should be appreciated that there is substantial confusion concerning which assays are indeed high sensitivity. From the perspective of this presentation, all assays presently in use except the high sensitivity cardiac troponin T (hscTnT) assay are considered conventional. Only the hscTnT assay of those available worldwide meets the metrics proposed for high sensitivity assays which include the ability to detect most if not all normal subjects.1
Commandment 1: collaborate with the laboratory and the emergency department
Analytical issues and how emergency department (ED) physicians think are often an anathema to clinicians. Collaboration is essential. Issues to be shared with the laboratory include when and how to evaluate potential false-positive and false-negative values, what cut-off values to use, and how to decide when a changing pattern is present. In regard to the ED, it is important to recognise that ED physicians never want to miss a patient at risk or to do so rarely. This means their practice, if they are unsure, is to admit patients. Since all patients with elevated cTn are at risk, many such patients are admitted. Those with a dynamic pattern require admission; however, many without a dynamic pattern can be evaluated as outpatients, but only if there is agreement concerning a facile pathway for that activity.
These issues will become more important with high sensitivity assays which are more prone to …