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[Serological diagnosis of Chagas disease: self-sufficiency and interlaboratory concordance]
V M Monteón1, C Guzmán-Bracho, J Floriani-Verdugo
1Departamento de Inmunología, Instituto Nacional de Cardiología Ignacio Chávez, México, D.F.
Insights
Chagas
Area of Science:
- Infectious Diseases
- Immunology
- Parasitology
Background:
- American trypanosomiasis (Chagas' disease) is an emerging health concern in North America.
- Diagnosing chronic Chagas' disease is challenging due to unreliable parasitologic and pathologic methods.
- Accurate diagnosis relies on detecting specific antibodies, necessitating standardized immunodiagnostic techniques and quality antigens.
Purpose of the Study:
- To standardize immunodiagnostic techniques for Chagas' disease in Mexico.
- To evaluate the quality of locally prepared antigens for Chagas' disease diagnosis.
- To compare the performance of indirect immunofluorescence, hemagglutination, and ELISA assays.
Main Methods:
- Comparison of locally prepared antigens from Mexican isolates (vector and human) using three immunodiagnostic assays.
- Assays included indirect immunofluorescence, hemagglutination, and enzyme-linked immunosorbent assay (ELISA).
- Testing was conducted across two reference laboratories in Mexico: Instituto Nacional de Cardiología and Instituto Nacional de Diagnóstico y Referencia Epidemiológicos.
Main Results:
- High concordance (Kappa value of 0.8) was achieved between the two laboratories.
- Individual diagnostic assays demonstrated adequate sensitivity, specificity, and predictive values.
- Locally prepared antigens proved suitable for use in clinical diagnosis.
Conclusions:
- Standardized immunodiagnostic techniques using quality local antigens are feasible for Chagas' disease diagnosis in Mexico.
- The study represents a significant first step in standardizing Chagas' disease diagnostics in the region.
- These validated methods support reliable clinical diagnosis of American trypanosomiasis.
Abstract:
American trypanosomiasis (Chagas' disease) is becoming a relatively common condition in North America. Diagnosis at the chronic stage depends on demonstration of specific antibodies in body fluids, since parasitologic or pathologic diagnosis is uncertain at this stage. Therefore, standardization of immunodiagnostic techniques is mandatory, and it depends on antigen quality. Locally prepared antigens and crude extracts obtained from Mexican isolates, -both from infected vector and human cases-were compared using three different immunodiagnostic assays-indirect immunofluorescence, hemagglutination and enzyme linked immunosorbent assay (ELISA)-at two different laboratories from the Instituto Nacional de Cardiología and the Instituto Nacional de Diagnóstico y Referencia Epidemiológicos. Concordance between laboratories reached a significant Kappa value (0.8) and sensitivity, specificity and predictive values of individual diagnostic assays were adequate to use these tests in clinical diagnoses. This is the first attempt to standardize immunodiagnostic techniques in Mexico.