MULTICENTER EVALUATION OF A 2ND-GENERATION ASSAY FOR CARDIAC TROPONIN-T

We report on the evaluation of the second-generation assay for cardiac troponin T (cTnT) on the Enzymun(R) system. This new assay is complet ely specific for the cardiac isoform of TnT, utilizing two cardiospeci fic monoclonal antibodies. The assay time is reduced to 45 min. The in terassay precision shows a median CV of 5.5%; 20% interassay CV was fo und between 0.05 and 0.1 mu g/L. The cardiosensitivity of the second-g eneration cTnT assay in patients with ischemic myocardial injury appea rs equivalent when compared with the first-generation assay. We found no falsely positive results in patients with skeletal muscle damage in cluding multitraumas, surgery patients, and marathon runners who showe d highly increased values with the unspecific first-generation assay. In Duchenne disease cTnT was still increased, but to a much lower exte nt. cTnT remains increased in renal failure, but to a lesser degree th an with the first-generation assay. The cause of this increase remains unclear. Although a cross-reactivity of skeletal muscle TnT in the se cond-generation assay could be excluded by our findings, minor myocard ial damage or expression of the cardiac isoform of TnT in regenerating muscles cannot be ruled out in those cases with apparently falsely in creased cTnT values. The second-generation cTnT assay is a step forwar d in the combination of cardiosensitivity and cardiospecificity in bio chemical markers for diagnosis of heart disease.