The state of cardiac troponin assays: looking bright and moving in the right direction.

Cardiac troponin assays have evolved substantially over 20 years, owing to the efforts of manufacturers to make them more precise and sensitive. These enhancements have led to high-sensitivity cardiac troponin assays, which ideally would give measureable values above the limit of detection (LoD) for 100% of healthy individuals and demonstrate an imprecision (CV) of 10% at the 99th percentile. Complete integration and proper use of high-sensitivity cardiac troponin assays into clinical practice will be an important step forward for the diagnosis of myocardial infarction and will allow cardiologists to use cardiac troponin as a prognostic indicator for risk-based outcomes assessment. As laboratorians, we wish to comment on the recently published “ACCF 2012 Expert Consensus Document on Practical Clinical Considerations in the Implementation of Troponin Elevations” (1 ). Our purpose is to address 8 analytical issues that we believe have the potential to cause confusion and that therefore deserve clarification. Input from the field of laboratory medicine is important for emphasizing our role as analytical-content experts in the process of strengthening our collaborative relationships with various clinical societies. Since the initial publications by the National Academy of Clinical Biochemistry (NACB) in 1999 and by the European Society of Cardiology/American College of Cardiology in 2000, when both organizations endorsed cardiac troponin I (cTnI) or cTnT as the preferred biomarker for the detection of myocardial infaction, numerous other organizations have followed suit and promoted the sole use of cardiac troponin in this clinical application. The American College of Cardiology Foundation (ACCF) 2012 Expert Consensus Document (1 ) summarizes the recently published 2012 Third Universal Definition of Myocardial Infarction by the Global Task Force (2 ), thus providing some practical recommendations on the use and interpretation of cardiac troponin in clinical practice. The integration and acceptance of cardiac troponin testing over the past 13 years has shown that the measurement of any other cardiac biomarkers for diagnostic use or risk assessment are unnecessary for patients presenting with symptoms suggestive of acute coronary syndromes. The analytical enhancements to cardiac troponin assays have provided clinicians and laboratorians with the needed confidence and ability to use the many automated and point-of-care (POC) assays currently available (3 ). Now, we wish to address the 8 analytical issues in question.