Cardiac Troponin Assay Classification by Both Clinical and Analytical Performance Characteristics: A Study on Outcome Prediction

BACKGROUND: Cardiac troponin assays have been clas-sified according to whether they measure the 99th per-centile concentration of a healthy reference population with imprecision (expressed as CV) of10%, between 10 % and 20%, or 20%. Assays in these categories have been deemed “guideline acceptable, ” “clinically usable, ” or “not acceptable, ” respectively. We com-pared four widely used “clinically usable ” cardiac tro-ponin I (cTnI) assays with an assay designated “not acceptable ” for accuracy in predicting the clinical out-come of death. METHODS: Blood was collected from 259 men and 249 women, mean (SD) age 68.8 (17.8) and 70.2 (17.8) years, respectively, admitted to the emergency depart-ment for suspected myocardial infarction. We mea