In medicine, as in all human communication, clear definitions are essential. The history of medicine is filled with examples of communication failures that result when poor definitions of specific disease entities are used. In clinical practice, as in clinical science, a clear definition of the disease diagnosed or studied is the initial, critical step in managing that illness. Accurate, clear definitions of a disease entity enable clinicians to communicate among themselves, to study the disease, and ultimately to explain to patients the specific condition from which the patient suffers. A clinical scientist’s diagnostic criteria must also be accurate and reproducible so that similar patients with the disease are studied and entered into clinical trials. When accurate, reproducible definitions of a specific disease entity are used, results from one clinical trial can be compared with the results from other trials, and clinicians can communicate accurately among themselves concerning a specific disease.

BIOMARKERS

Given the worldwide importance of morbidity and mortality of cardiovascular disease, considerable scientific effort has been expended in order to identify laboratory tools for clearly and accurately defining the various syndromes of acute ischaemic heart disease. One such modern tool involves the use of biomarkers. Biomarkers are adjunctive tests employed alongside clinical findings to aid physicians in making accurate clinical diagnoses.^w1 Various biomarkers have been used for decades in patients with acute ischaemic heart disease; however, the advent of highly specific troponin assays has significantly improved identification of patients with acute ischaemic heart disease. Risk stratification of these patients has also been aided by the use of the troponin measurements in daily clinical practice. The biomarker troponin is the most sensitive and specific test yet devised for identifying myocardial cell necrosis.

The use of troponin blood assays to define various syndromes of acute ischaemic heart disease has gained worldwide …