Update on quality specifications for cardiac troponin assays

Assay-related issues still markedly influence the clinical performance of cardiac troponin (cTn). This chapter updates recommendations on achievable quality specifications for cTn assays for assay manufacturers, laboratorians and clinicians. The recommendations provided pertain to pre-analytical and analytical characteristics, postanalytical implementation and clinical practice. They are based on the evidence based literature and expert opinion of the authors when evidence is lacking. cTnI assay harmonization is still not on the horizon and interchangeable cTnI assay medical decision limits are not expected in the near future. The influence of anticoagulants, imprecision, limits of blank, lower limit of detection, linearity, interferences, and method comparison should be obtained following standard Clinical and Laboratory Standards Institute (CLSI) guidelines. Guidance for the determination of the 99^th percentile concentration and biological variation determinations in healthy individuals and basics on the clinical assessment of cTn changes in serial testing are given. The recommendations provided should be universally achievable. They provide guidance for cTn assay manufacturers to harmonize information in their package inserts and for laboratorians and clinicians to optimally measure and interpret cTn concentrations in everyday clinical practice.