Rapid, Highly Sensitive Immunoassay for Determination of Cardiac Troponin I in Patientswith Myocardial Cell Damage

The aim of this study was to validate a new automated cardiac troponin I (cTnI) assay developed by Sanofi Diagnostic Pasteur (Marnes la Coquette, France) on the Access immunoassay system from the same manufacturer, and to evaluate its diagnostic sensitivity for early detection of myocardial damage. The assay is a two-site sandwich, immuno-chemiluminometric ELISA using two monoclonal antibodies that recognize different epitopes unique to the human cTnI isoform (1). Pipetting, incubations, measurements, and data-reduction steps are performed on the Access analyzer, which produces the first test result in 20 min. The minimum detectable cTnI concentration, assessed by 10 replicate measurements in a single run of the zero calibrator serum supplied with the kit and defined as the cTnI value corresponding to the signal 3 SD greater than the mean found for this calibrator, was estimated as 0.01 μg/L. The assay measured cTnI in serum and EDTA-anticoagulated plasma in the same way: Fresh specimens collected at the same time from subjects (n = 24) with an increased concentration of cTnI gave similar results for serum and EDTA-plasma (0.49 ± 0.78 vs 0.46 ± 0.74 μg/L, respectively; P = 0.48). Assay reproducibility was tested by assaying three control materials (from Sanofi) containing human cTnI at …