ISSN: 0034-8376
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ABSTRACT

The Type of Trypanosoma Cruzi Strain (Native or Non-Native) Used as Substrate for Immunoassays Influences the Ability of Screening Asymptomatic Blood Donors

VOLUME 68 - NUMBER 6 / November - December (Brief Communications)

Martha A. Ballinas-Verdugo, Departments of Molecular Biology, Immunology Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
Ana M. Mejía-Domínguez, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
Sergio A. Sánchez-Guerrero, Instituto Nacional de Cancerología, Mexico City, Mexico
Claudia Lerma, Departments of Electromechanic Instrumentation, Instituto Nacional de Cardiología Ignacio Chávez
Mariana Martínez-Cruz, Perronee-Gatonee Veterinary Clinics, Mexico City, Mexico
Elsa Álvarez-Manilla-Toquero, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
Xochiquetzali Jiménez-Díaz, Instituto Nacional de Cancerología, Mexico City, Mexico
Francelia Barrera-Trujillo, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
Marisela del R. Ticante-Cruz, Instituto Nacional de Cancerología, Mexico City, Mexico
Irving O. Estevez-Garcia, Departments of Immunology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
Luis M. Amezcua-Guerra, Departments of Immunology, Instituto Nacional de Cardiología Ignacio Chávez, and Health Care Department, Universidad Autónoma Metropolitana, Mexico City, Mexico
Pedro A. Reyes-Lopez, Division of Research, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico

Background: The origin (native or non-native) of Trypanosoma cruzi strains used as substrate for immunoassays may influence their performance. Objective: To assess the performance of an immunoassay based on a native T. cruzi strain compared to another based on non-native T. cruzi strains, in asymptomatic blood donors from Mexico. Methods: Serum samples from a tertiary referral center were tested by both ELISA-INC9 (native) and Chagatest (non-native) assays. All reactive serum samples were further analyzed by indirect immunofluorescence. Results: Sera from 1,098 asymptomatic blood donors were tested. A 4.3 and 0.7% serum reactivity prevalence was observed using ELISA-INC9 and Chagatest, respectively (kappa = 0.13; −0.11 to 0.38). Subsequently, indirect immunofluorescence analyses showed higher positivity in serum samples reactive by ELISA-INC9 compared to those reactive by Chagatest (79 vs. 62.5%; p < 0.001). Furthermore, out of the 47 positive samples by both ELISA-INC9 and indirect immunofluorescence, only four (8.5%) were reactive in Chagatest assay. Meanwhile, four (80%) out of the five positive samples by both Chagatest and indirect immunofluorescence were reactive using ELISA-INC9. Conclusion: Immunoassays based on a native T. cruzi strain perform better than those based on non-native strains, highlighting the need to develop and validate screening assays in accordance to endemic T. cruzi strains.

Keywords: Chagas disease. Trypanosoma cruzi. Immunoassay.

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