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Chagas' disease screening in blood bank employing enzyme immunoassay
L M Knecher1, L F Rojkín, G A Capriotti
1Wiener Laboratory, S.A.I.C., Rosario, Argentina.
Insights
A new enzyme immunoassay for Trypanosoma cruzi infection offers improved accuracy and automation for blood bank screening. This diagnostic tool enhances detection of Chagas disease, crucial for public health in endemic and non-endemic regions.
Area of Science:
- Immunology
- Parasitology
- Medical Diagnostics
Background:
- Trypanosoma cruzi infection (Chagas disease) is prevalent in Latin America, necessitating blood bank screening.
- Current screening methods for Chagas disease lack objectivity and automation, posing challenges for large-scale laboratories.
- Increasing migration and donor frequency from Latin America raise concerns for Chagas disease screening in the U.S.A.
Purpose of the Study:
- To develop a novel enzyme immunoassay (EIA) for detecting antibodies against Trypanosoma cruzi.
- To improve the sensitivity, specificity, and objectivity of Chagas disease antibody screening.
- To create a diagnostic method suitable for automated laboratory procedures.
Main Methods:
- Development of an EIA utilizing a mixture of purified parasite antigens (membrane and cytoplasm).
- Testing of 661 patient samples from various Chagas disease stages, 120 from other parasitoses, and 880 normal subjects.
- Comparison of EIA results with established methods like indirect hemagglutination, direct agglutination, immunofluorescence, and latex agglutination assays.
Main Results:
- The developed EIA demonstrated superior reproducibility, specificity, and sensitivity compared to reference methods.
- The assay allows for objective interpretation of results, either spectrophotometrically or visually.
- The procedure is efficient, with a 90-minute total incubation time and two washing steps, suitable for automation.
Conclusions:
- The novel enzyme immunoassay provides a more accurate and reliable method for Trypanosoma cruzi antibody detection.
- This EIA offers objective results and automation compatibility, addressing limitations of current Chagas disease screening tests.
- The improved diagnostic tool is valuable for blood bank screening and managing Chagas disease in diverse populations.
Abstract:
Because of the high prevalence of Trypanosoma cruzi infection in Latin America, antibody screening in blood banks is mandatory in this area. This screening may also become a concern in the U.S.A. considering the high frequency of Latin American donors. The tests usually employed (indirect hemagglutination, direct agglutination, immunofluorescence and latex agglutination assays) involve subjective interpretation of results and do not fit the automated procedures requirements of large laboratories. Thus, an enzyme immunoassay was developed using a mixture of antigens purified from the membrane and the cytoplasm of the parasite. Serum of plasma could be used as sample, in a procedure involving 90 min total incubation time and 2 washing steps. Results could be interpreted either spectrophotometrically or by the naked eye. The method was used to test 661 samples from patients undergoing different stages of Chagas' disease, 120 patients suffering other parasitosis and 880 normal subjects. Results were compared with those obtained with the methods mentioned above. The proposed test showed better reproducibility, specificity and sensitivity than those of reference methods, plus an objective interpretation of results and suitability to automation.