Validity of serology for American Trypanosomiasis with eluates from filter paper

Abstract

This study evaluates whether blood collected on filter paper kept at 4 degrees C and tested at different intervals of time (1, 7, 15, 30 and 60 days after collection) would present similar results when compared to the serum samples and whether the type of filter paper influences the results. Eluates from filter paper samples were tested for Trypanosoma cruzi antibodies using indirect immunofluorescence antibody test (IFAT), indirect haemagglutination (IHA) and enzyme-linked immunosorbent assay (ELISA) as reference, the antibody titer in sera. Analysis of data showed that results obtained with IFAT, IHA (cut off point = 1:40) and ELISA in sera had similar sensitivity and good concordance among reactions. The use of a multiple linear regression model indicated that titer fall in eluates occurs up to the 7th day after the collection, and it is more marked for samples with lower antibodies titers. However, no significant differences were observed by IFAT, IHA (cut off point = 1:20) and ELISA in the proportion of positive reactions between sera and eluates. The results also showed that Melitta, Klabin or Whatman (reference) filter papers could be indicated for surveys, since they have shown similar capacity of maintenance of anti-T. cruzi immunoglobulins.

Efficacy of serum samples stored on filter paper for the detection of antibody to Leptospira spp. by microagglutination test (MAT)

“…30 30 30 29 29 6400 18 18 18 19 19 3200 34 34 34 34 34 1600 32 32 32 32 32 800 22 22 22 22 22 400 8 8 8 8 8 200 7 7 7 7 7 Negative 144 144 144 144 144 Total 300 300 300 300 performance of studies using sera from remote locations is greatly facilitated if serum samples dried on filter paper are shown to be compatible with the serologic assay being employed. These data confirm previously reported results with other infectious diseases (Zicker et al, 1990;Roy et al, 1992Roy et al, , 1994Ruangturakit et al, 1994;Machado-Coelho et al, 1995;Jafri et al, 1998;Fenollar and Raoult, 1999;Luquetti et al, 2003;El Mubarak et al, 2004;Mehta et al, 2009) showing that antibodies remain stable in sera stored or transported after drying on filter paper. This would be important in instances where sera need to be transported or mailed in a biosafety envelope to another laboratory.…”

Seroprevalencia de anticuerpos contra Trypanosoma cruzi y su asociación con factores de riesgo en menores de 18 años de Veracruz, México

“…En el presente estudio, la prevalencia en menores de 18 años fue de 0,91%. La correlación encontrada entre los resultados obtenidos a partir de las muestras fijadas en papel de filtro y de los sueros respectivos es baja, posiblemente debido a artefactos en las determinaciones realizadas con las primeras, por la exposición a condiciones inadecuadas de almacenamiento y transportación (39).…”

Evaluation of enzyme-linked immunosorbent assay using crude Leishmania and recombinant antigens as a diagnostic marker for canine visceral leishmaniasis

“…Eluates of blood dried on filter paper are commonly used in laboratory tests and the validity of this technique has been confirmed for the diagnosis of leishmaniasis , Gomes et al 2001 and for other infections such as toxoplasmosis and Chagas disease (Chiari et al 1987, Machado-Coelho et al 1995.…”