The mystifying nomenclature of cardiac troponin immunoassays.

ABSTRACT

The laboratory assessment of cardiospecific troponins(s) represents the cornerstone for the diagnosis of acute coronary syndrome (ACS). Although troponin immunoassays are classified according to either analytical imprecision or percentage of measurable values in a presumably healthy population, it is rather clear that the nomenclature of commercial methods according to these systems of classification carries several drawbacks. The leading problems in classification according to imprecision are represented by the arbitrarity of optimal imprecision threshold, the uncertain correspondence between analytical performance and clinical outcomes and the improper use of terms, which has also been magnified by the lack of specific focus on this topic by regulating bodies such as the US Food and Drug Administration (FDA) and the European Union. Additional issues emerging from classification according to percentage of measurable values include the characterization of healthy population, the variation of values according to age, gender and race, as well as the influence of comorbidities. Considering that what really matters from a clinical standpoint is the clinical performance of the assay rather than the claimed analytical characteristics, it seems reasonable at this point in time to introduce a paradigm shift and gradually abandon the former analytical classification in favour of a different approach, preferable based on clinical outcomes.