The hitchhiker’s guide to the troponin universe

Abstract

Pathology Queensland consists of a network of 34 laboratories spread throughout Queensland. In 2007, biochemistry testing was standardised state-wide with the introduction of Beckman Coulter analysers. Their accuTnI assay was used for measuring cardiac troponin I. Simultaneously, the Universal Definition of Myocardial Infarction, as defined in 2000, was introduced with a new cardiac troponin I cut-off level according to the 99^th percentile. A number of issues ensued. The diagnosis of myocardial infarction increased dramatically straining emergency and cardiology resources. Unexpectedly, randomly occurring false positive results (flyers) were identified that had a significant impact on clinical intervention. ‘Highly sensitive' cardiac troponin assays were introduced into the market adding to the conundrum. We report more than 300 000 cardiac troponin I tests annually. Our experience with cardiac troponin testing will be presented as well as our research findings into the performance of troponin assays. Unlike our fictional Hitchhiker's Guide we have pursued analytical performance relentlessly. We have characterised assay robustness and between-assay variance, and presented guidance on how to universally define significant changes in serial cardiac troponin results. I will entertain our perspective regarding the value of ‘highly sensitive' cardiac troponin.