[High-sensitivity troponin assay: biochemistry and clinical application]

Cardiac troponin is the marker of choice for the diagnosis of acute coronary syndrome. Its introduction in clinical practice consistently improved both sensibility and specificity as compared with other biomarkers, as creatin-chinase MB. However traditional troponin assays show some limits: the relatively long time elapsing between the onset of ischemia and the increase in serum concentration, and the difficulty in distinguishing ischemic from non ischemic damage. An earlier diagnosis could be obtained by adopting new high sensitivity troponin assays, with a coefficient of variation ≤10% at the 99° percentile of a reference healthy population, and capable of detecting circulating troponin in the most healty subjects. The difficulty in distinguishing ischemic from non ischemic harm can be overcome considering that only a rising and falling pattern can be attributed to ischemic harm. Further studies are needed to evaluate the prognostic role of low circulating troponin levels in healthy subjects and for properly fixing cut off values. Indeed biomarker increase has always to be considered in the specific clinical context.