The analytical performance of an immunoenzymometric assay for the cardiac troponin (cTnI) has been appraised and compared with other methods.
The test is a two-site immunoenzymometric assay, which uses a combination of two monoclonal antibodies, respectively directed to 41–49 and 87–91 amino acids of the cTnI peptide chain, and the ternary troponin ITC complex as a calibration antigen.
Scientists at the Fondazione Toscana G. Monasterio (Pisa, Italy) evaluated the assay in 452 healthy individuals of which 326 were males and 126 were female. The median age was 45 years with a range between 17 to 76 years. The study participants were recruited from laboratory staff, blood donors, or voluntary subjects, included in screening programs for preventive medicine.
The immunoenzymometric assay for the cTnI evaluated in the study was the Tosoh ST AIA-PACK cTnI 3rd-Generation, and it uses the automated AIA-2000 platform (Tosoh Corporation, Tokyo, Japan). The third-generation AIA-Pack assay for cTnI showed an improved analytical sensitivity and reproducibility, especially at very low cTnI concentrations compared to the previous second-generation AIA-Pack assay. The values of the third-generation assay were a limit of detection (LoD) at 8.7 ng/L and the limit of quantitation (LoQ) at 100 ng/L. The LoD and 10% LoQ values of the second-generation assay reported previously were 38 ng/L and 130 ng/L, respectively.
The third-generation AIA-Pack Tosoh assay for cTnI showed a very close agreement throughout all the working range with the Access AccuTnI Beckman–Coulter method (Beckman Coulter, Inc.; Fullerton, CA, USA). Close concordance was also demonstrated between the cTnI measured by Tosoh methods and those of cTnT measured with ECLIA Roche method (Roche Diagnostics, Mannheim, Germany). The authors concluded that their results imply that the third generation AIA-Pack assay is suitable for the clinical evaluation of patients with cardiac diseases. The study was published in the January 2013 issue of the journal Clinica Chimica Acta.