Evaluation of Three Commercial Enzyme-Linked Immunosorbent Assays for Diagnosis of Chagas’ Disease

Abstract

Chagas’ disease is a common cause of morbidity in Latin American countries. In Brazil, naturally occurring transmission of its etiologic agent, Trypanosoma cruzi, has been almost completely abolished through effective control programs aimed at the triatomid insect vector. Thus, transfusion of blood from infected donors has become the major route for contracting Chagas’ disease due to the socioeconomically motivated migration of residents from areas where the disease is endemic to the larger urban centers. Therefore, the employment of screening tests is mandatory for all blood banks throughout the country. We compared the diagnostic performances of three commercially available screening assays used in routine testing in Brazilian blood banks: the Abbott Chagas antibody enzyme immunoassay (Abbott Laboratórios do Brasil, São Paulo), the BIOELISACRUZI kit (Biolab-Mérieux, Rio de Janeiro, Brazil), and the BIOZIMA Chagas kit (Polychaco S.A.I.C., Buenos Aires, Argentina). The evaluation was performed with sera obtained from chagasic patients and healthy residents of four different areas in Brazil where Chagas’ disease is either endemic or emergent and where clinical manifestations of the disease and circulating parasite strains vary. The results obtained with each kit were compared to matched in-house enzyme-linked immunosorbent assay and immunofluorescence assay data obtained for each sample. Depending on the area under investigation, the three commercial kits produced specificity values between 93.3 and 100.0%, sensitivity values between 97.7 and 100%, and accuracies ranging from 93.6 to 100.0%.

An improved serodiagnostic test for Chagas' disease employing a mixture of Trypanosoma cruzi recombinant antigens

“…The variation in the diagnostic performance of conventional serology is not surprising since the semipurified antigenic preparations employed in these tests may contain epitopes that have different affinities for both specific and nonspecific antibodies, thus accounting for conflicting results (see Table 3). 28 Our data, and those from other laboratories, indicate that recombinant antigens and synthetic peptides provide more specific alternatives to the complex crude extracts of epimastigotes used in the commercial kits. We further show that the sensitivity of the recombinant antigen mixture is equivalent to that of the TESA blot test.…”

“…The commercially available kits employ different preparations of epimastigote forms of T. cruzi, which can introduce a source of variability in the final reagent, and controversial results can be obtained. 8,28 In busy routine diagnostic centers (blood banks, hospitals, etc. ), the sensitivity of the commercial conventional tests is about 95 percent (specificities range from 93% to 98%), indicating that no single test for Chagas' disease is sensitive enough to prevent the risk of T. cruzi transmission by transfusion.…”

“…), the sensitivity of the commercial conventional tests is about 95 percent (specificities range from 93% to 98%), indicating that no single test for Chagas' disease is sensitive enough to prevent the risk of T. cruzi transmission by transfusion. 3,4,17,28 To overcome this problem, several laboratories have been working on the development of second-and thirdgeneration serodiagnostic tests based on the combination of different recombinant proteins or synthetic peptides. [16][17][18][20][21][22]29 In a previous work, we determined the sensitivity and specificity of six T. cruzi recombinant antigens tested individually with a panel of sera from chronic chagasic and nonchagasic patients, from different geographic regions of Latin America.…”

“…TESA fractions were separated electrophoretically on 7 percent SDS-PAGE gels, blotted onto nitrocellulose membranes, and probed with sera. 1,28 The immune complexes were revealed after incubation with 1 in 4000 diluted anti-human IgG peroxidase conjugate by addition of H 2 O 2 and 4-chloro-1-naphthol, as described. 24 All the chronic chagasic patients samples recognized a broad band of 150 to 160 kDa.…”

Estimation of sensitivity and specificity of several Trypanosoma cruzi antibody assays in blood donors in Argentina

“…The following available assays were employed: Chagatek (EIA BioM; Lemos Laboratory, commercialized by BioMerieux Lab., Buenos Aires, Argentina), Chagas BiosChile (EIA BiosCh; BiosChile, Santiago, Chile) and BioZima Chagas (EIA BioZ; Lemos Laboratory, Buenos Aires, Argentina), 19…”