Edging Closer to Early Optimal Patient Management With High-Sensitivity Cardiac Troponin Assay

These are exciting times in the evolution of cardiac biomarkers. In the past 12 years, we have witnessed the transition from creatine kinase-MB to cardiac troponin I (cTnI) and T (cTnT) as the standard biomarkers to aid in the diagnosis of acute myocardial infarction (MI). This is evidenced by the overwhelming endorsement through recommendations from laboratory medicine,1 cardiology,2 and emergency medicine.3 At present, the biomarker field is moving forward with an analytic advancement of technologies to be able to measure both cTnT and cTnI for the precise measurement at concentrations within normal reference subjects. High-sensitivity cardiac troponin assays show great promise for earlier diagnostic accuracy for detection of MI,4 improved triage of patients to allow for better outcomes assessment of low-risk acute coronary syndrome patients,5 and to address a role in primary prevention as a necessary tool to assist clinicians in all cardiovascular evaluations.6,7 What distinguishes these new high-sensitivity assays from their predecessors is the ability to measure very low cTnT and cTnI concentrations (1 to 20 pg/mL, which equals 0.001 to 0.020 μg/L, well below the limit of detection of the sensitive and contemporary assays used in clinical practice today), with an excellent imprecision (coefficient of variation ≤10%) at and below the assay's 99th percentile value. This added sensitivity allows high-sensitivity cardiac troponin assays to reliably measure concentrations in almost 100% of healthy individuals. Contemporary assays can typically measure cardiac troponin values in only 10% to 20% of individuals from the general, apparently healthy population.8Article see p 136The role that the biomarker cardiac troponin occupies in assisting in the diagnosis of MI is further solidified in the findings presented by Reichlin …