New sensitive cardiac troponin assays for the early diagnosis of myocardial infarction.

The objective of the current article is to review and evaluate the diagnostic and prognostic value of a new generation of sensitive assays for cardiac troponin I and troponin T. Cardiac-specific troponins I and T are the preferred diagnostic biomarker in patients presenting with suspected acute coronary syndromes. One important limitation of previous generation assays has been the relative insensitivity in detecting myocardial injury in patients with a short duration from symptom onset to presentation in the emergency room. Recently, sensitive assays for cardiac troponins I and T have been introduced as research tools and in clinical practice. Clinical trials evaluating these assays have demonstrated that sensitivity and overall diagnostic accuracy for acute myocardial infarction, defined by the 99th percentile cardiac troponin concentration in a healthy population, is enhanced, although at the cost of reduced specificity. Not surprisingly, the relative benefit compared to previous generation assays is greatest for those patients presenting early after symptom onset. A number of cardiac conditions other than acute coronary syndromes, as well as several noncardiac conditions, are associated with elevation of circulating cardiac troponins. Thus, with the use of more sensitive assays, clinical context and serial testing to document a rise and/or fall in concentrations will be increasingly important for correct interpretation of troponin results.