title: Chronic Chagas Disease Diagnosis: A Comparative Performance of Commercial Enzyme Immunoassay Tests.
abstract: There is a significant heterogeneity in reported performance of serological assays for Chagas disease diagnosis. The conventional serology testing in laboratory diagnosis and in blood banks is unsatisfactory because of a high number of inconclusive and misclassified results. We aimed to assess the quality of four commercially available enzyme-linked immunosorbent assay tests for their ability to detect Trypanosoma cruzi antibodies in 685 sera samples. Cross-reactivity was assessed by using 748 sera from patients with unrelated diseases. Initially, we found that the reactivity index against T. cruzi antigen was statistically higher in sera from Chagas disease patients compared with those from non-chagasic patients, supporting the notion that all evaluated tests have a good discriminatory ability toward the diagnosis of T. cruzi infection in patients in the chronic phase of the disease. Although all tests were similarly sensitive for diagnosing T. cruzi infection, there were significant variations in terms of specificity and cross-reactivity among them. Indeed, we obtained divergent results when testing sera from patient with unrelated diseases, particularly leishmaniasis, with the levels of cross-reactivity being higher in tests using whole T. cruzi extracts compared with those using recombinant proteins. Our data suggest that all four tests may be used for the laboratory diagnosis and routine blood screening diagnose for Chagas disease. We also emphasize that, despite their general good performance, caution is needed when analyzing the results when these tests are performed in areas where other diseases, particularly leishmaniasis, are endemic.
authors.affiliation: Reference Laboratory for Chagas Disease, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Department of Public Health, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Carlos Chagas Institute-Molecular Biology Institute of Paraná, Fundação Oswaldo Cruz, Curitiba, Brazil fred.santos@cpqam.fiocruz.br.
authors.forename: Fred Luciano Neves
authors.initials: FL
authors.lastname: Santos
authors.affiliation: Reference Laboratory for Chagas Disease, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Department of Public Health, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Carlos Chagas Institute-Molecular Biology Institute of Paraná, Fundação Oswaldo Cruz, Curitiba, Brazil.
authors.forename: Wayner Vieira
authors.initials: WV
authors.lastname: de Souza
authors.affiliation: Reference Laboratory for Chagas Disease, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Department of Public Health, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Carlos Chagas Institute-Molecular Biology Institute of Paraná, Fundação Oswaldo Cruz, Curitiba, Brazil.
authors.forename: Michelle da Silva
authors.initials: Mda S
authors.lastname: Barros
authors.affiliation: Reference Laboratory for Chagas Disease, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Department of Public Health, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Carlos Chagas Institute-Molecular Biology Institute of Paraná, Fundação Oswaldo Cruz, Curitiba, Brazil.
authors.forename: Mineo
authors.initials: M
authors.lastname: Nakazawa
authors.affiliation: Reference Laboratory for Chagas Disease, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Department of Public Health, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Carlos Chagas Institute-Molecular Biology Institute of Paraná, Fundação Oswaldo Cruz, Curitiba, Brazil.
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Krieger
authors.affiliation: Reference Laboratory for Chagas Disease, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Department of Public Health, Aggeu Magalhães Research Center, Fundação Oswaldo Cruz, Recife, Brazil; Carlos Chagas Institute-Molecular Biology Institute of Paraná, Fundação Oswaldo Cruz, Curitiba, Brazil.
authors.forename: Yara de Miranda
authors.initials: Yde M
authors.lastname: Gomes
mesh_terms: D002598:Chagas Cardiomyopathy / Q000097:blood / Q000175:diagnosis*; D002908:Chronic Disease; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*