WHO comparative evaluation of serologic assays for Chagas disease

Authors

  • Marcia M. Otani,

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • Elizabeth Vinelli,

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • Louis V. Kirchhoff,

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • Ana Del Pozo,

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • Anita Sands,

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • Gaby Vercauteren,

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • Ester C. Sabino

    1. From the Fundação Pró-Sangue, Hemocentro de São Paulo, and the School of Medicine, University of São Paulo, São Paulo, Brazil; Programa de Sangre, Cruz Roja Hondureña, Tegucigalpa, Honduras; the Departments of Internal Medicine and Epidemiology, University of Iowa, and the Department of Veterans Affairs Medical Center, Iowa City, Iowa; Servicio de Hemoterapia, Hospital de Pediatría Prof. Dr Juan P. Garrahan, Buenos Aires, Argentina; and Essential Health Technologies, World Health Organization, Geneva, Switzerland.
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  • This study was supported by a grant from WHO.

Ester C. Sabino, MD, PhD, Department of Molecular Biology, Fundação Pró-Sangue, Hemocentro de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 155, 1° andar, 05403-000 São Paulo, SP, Brazil; e-mail: sabinoec@uol.com.br.

Abstract

BACKGROUND: Evaluation of commercially available test kits for Chagas disease for use in blood bank screening is difficult due to a lack of large and well-characterized specimen panels. This study presents a collaborative effort of Latin American blood centers and the World Health Organization (WHO) to establish such a panel.

STUDY DESIGN: A total of 437 specimens, from 10 countries were collected and sent to the WHO Collaborating Center in São Paulo and used to evaluate 19 screening assays during 2001 through 2005. Specimens were assigned a positive or negative status based on concordant results in at least three of the four confirmatory assays (indirect immunofluorescence, Western blot, radioimmunoprecipitation assay, and recombinant immunoblot).

RESULTS: Of the 437 specimens, 168 (39%) were characterized as positive, 262 (61%) were characterized as negative, and 7 (2%) were judged inconclusive and excluded from the analysis. Sensitivity and specificity varied considerably: 88 to 100 and 60 to 100 percent, respectively. Overall, enzyme immunoassays (EIAs) performed better than the other screening assays. Four EIAs had both parameters higher than 99 percent. Of the four confirmatory assays, only the RIPA gave a 100 percent agreement with the final serologic status of the specimens.

CONCLUSION: The sensitivities and specificities of at least four of the commercially available EIAs for Chagas disease are probably high enough to justify their use for single-assay screening of blood donations. Our data suggest that the majority of commercially available indirect hemagglutination assays should not be used for blood donor screening and that the RIPA could be considered a gold standard for evaluating the performance of other assays.

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