Serodiagnosis of Trypanosoma cruzi infection using the new particle gel immunoassay - ID-PaGIA Chagas

The ID-Chagas test is a particle gel immunoassay (PaGIA). Red coloured part icles are sensitised with three different synthetic peptides representing a ntigen sequences of Trypanosoma cruzi: Ag2, TcD and TcE. When these particl es are mixed with serum containing specific antibodies, they agglutinate. T he reaction mixture is centrifuged through a gel filtration matrix allowing free agglutinated particles to remain trapped on the top or distributed wi thin the gel. The result can be read visually. In order to investigate the ability of the ID-PaGIA to discriminate negative and positive sera, 111 neg ative and 119 positive, collected in four different Brazilian institutions, were tested by each of the participants. All sera were previously classifi ed as positive or negative according to results obtained with three convent ional tests (indirect immunofluorescence, indirect hemaglutination, and enz ime linked immunosorbent assay). Sensitivity rates of ID-PaGIA varied from 95.7% to 97.4% with mean sensitivity of 96.8% and specificity rates varied from 93.8 to 98.8% with mean specificity of 94.6%. The overall Kappa test w as 0.94. The assay presents as advantages the simplicity of operation and t he reaction time of 20 min. In this study, ID-PaGIA showed to be highly sen sitive and specific.