Cardiac Biomarkers in Acute Coronary Syndrome

Abstract

Acute coronary syndrome (ACS) is one of the leading causes of admission to the emergency departments (EDs) worldwide. The diagnosis of ACS involves the evaluation of clinical signs and symptoms, electrocardiographic assessment, and measurement of cardiac circulating biomarkers. In the last 60 years, the use of laboratory markers has changed considerably. Early biomarker assessment has entailed testing for total enzyme activity of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase (CK) but was highly nonspecific. Soon thereafter, the development of immunoassays, as well as technical advances in automation, allowed the measurements of the CK MB isoenzyme (CK-MB) in mass rather than in activity and myoglobin. Currently, cardiac troponins (CTn) have the highest sensitivity and specificity for myocardial necrosis and represent the biochemical gold standard for diagnosing acute myocardial infarction (AMI). This review provides a chronology of the major events that marked the evolution of cardiac biomarker testing and the development of the relative assays from the first introduction of AST in the 1950s to the last high-sensitivity troponin immunoassays in the 2010s.