Standardization of Cardiac Troponin I Measurements: The Way Forward?

The contribution of laboratory medicine to clinical cardiology has grown in importance over the years. Highly sensitive and specific biomarkers for the detection of myocardial damage, such as cardiac troponins, as well as assays for reliable markers of myocardial function, such as cardiac natriuretic peptides, are now available, assigning to the laboratory a pivotal role in the diagnosis and follow-up of patients with cardiac disease (1). This has been evidenced by the incorporation of these markers into new international guidelines (2)(3)(4). Among those, one of the most important documents outlines the recommendations for a new definition of myocardial infarction (MI), published by the joint European Society of Cardiology and American College of Cardiology committee (2). This consensus document has based the MI definition on biochemical grounds, a choice guided by the advent of cardiac troponins, biomarkers that provide higher sensitivity for smaller myocardial injury and virtually total specificity for cardiac damage (5). It is therefore important that these clinically relevant biomarkers, on which critical decisions will rest, are measured with highly reliable and standardized methods to achieve comparability of results, independent of the measurement test reagents and platforms as well as the laboratory where the procedure is carried out (6). Interchangeability of results over time and location would contribute considerably to improvements in healthcare because results of clinical studies undertaken in different locations or at different times could be universally applied. This would allow effective application of evidence-based medicine, as guidelines established by scientific or professional bodies often advocate use of specific decision limits for diagnosis and therapeutic intervention (3).Because of an international patent, cardiac troponin T assays from only a single diagnostic manufacturer are commercially available, so that comparability of results for this marker is not a problem. Conversely, more than 15 different …