Troponin--past, present, and future.

Cardiac troponin is the analyte of choice for the diagnosis of cardiac injury. It is highly specific for the heart and much more sensitive than prior biomarkers. Because of this increased sensitivity, clinicians have had to struggle with elevations in novel clinical situations. We have developed new understandings about coronary artery disease but also have begun to appreciate that many other entities as well can result in cardiac injury. As assays have increased in sensitivity over time, this trend has, if anything, accelerated. This review attempts to put the past, the present, and the future into a clinical perspective that will help clinicians.