Earlier detection of myocardial infarction by an improved cardiac TnI assay

Objectives: The aim of this study was to establish the diagnostic sensitivity of combinations of well-selected monoclonal antibodies (mAbs) against cardiac troponin I (cTnI) to allow an earlier rule-in of acute coronary syndrome (ACS) patients. Design and methods: Using several combinations of mAbs, four new experimental cTnI immunoassays were evaluated to analyze plasma samples from 62 patients suffering from angina (16/62), patients having a chest pain of extracardiovascular origin (19/62) and ACS without ST elevation (NSTE-ACS) (27/62). Results: Assay 2, which relies on a capture mAb directed against the central part of cTnI and two conjugated mAbs directed against the N-ter region, provided the best clinical sensitivity. In 11 out of 27 patients with NSTE-ACS, it detected an early rise of cTnI within 0 and 1 h upon admission, contributing to the detection of 53% of samples found to be negative by the reference AccuTnI Assay upon admission (Beckman Coulter), thereby reducing the delay in diagnosis. Conclusions: Assay 2 can identify early cTnI elevation in NSTE-ACS, possibly facilitating the rule-in procedure for these patients once the assay is automated.