The Laboratory Diagnosis of Myocardial Infarction and Heart Failure

The acute coronary syndrome (myocardial infarction and unstable angina) and heart failure afflict millions of people each year, and the use of biomarkers, coupled with clinical examination and other studies, are required to diagnose these conditions. Following ischemic injury to cells, cell membrane integrity is compromised, allowing intracellular constituents to leak into the blood. Important parameters that determine the usefulness of a cellular constituent as a biomarker include cellular location (cytosolic components reach the blood faster than structural components), molecular size (smaller components reach the blood faster than larger components), and tissue specificity (markers more specific for cardiac tissue provide more assay specificity than those that are less specific for cardiac tissue). Unfortunately there is no biomarker that is completely specific for diagnosis of myocardial infarction.