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Published on: January 27, 2019
Validation of a particle gel immunoassay for Trypanosoma cruzi antibody detection using plasma samples collected with
Marlene M Y Kawai1, Jose A P Salas, Luiz A P Tavares
1Hospital Universitario Julio Muller, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil.
Introduction:
The Chagas disease particle gel immunoassay (PaGIA-Chagas) is a simple, fast and practical test used for the diagnosis of the chronic Chagas disease and is based on anti-Trypanosoma cruzi antibody detection in serum. This study aimed to validate the PaGIA-Chagas on plasma collected with capillary tubes.
Methodology:
Serum samples from 74 T. cruzi-infected and 26 non-infected individuals were tested by conventional indirect immunofluorescence and PaGIA-Chagas. Later, plasma specimens collected with capillary tubes from these same individuals were tested by PaGIA-Chagas. Results from serum samples tested by IFA and PAGIA- Chagas were considered as the reference standard to determine the accuracy parameters of the particle gel tested on plasma samples. The inter-test agreement of T. cruzi antibody detection by PaGIA-Chagas on serum and plasma was calculated using Kappa index.
Results:
The PaGIA-Chagas performed on plasma collected with capillary tubes had sensitivity and specificity of 99% and 100%, respectively. The crude agreement observed with the results of the PaGIA-Chagas on plasma and serum was 99% and the Kappa index was 0.975 (CI95%: 0.782 - 1.000).
Conclusion:
PaGIA-Chagas for anti-T. cruzi detection on plasma collected with capillary tubes is accurate and might be indicated to reduce fieldwork time and materials in epidemiological screening of chronic Chagas disease.

