Padronização de um teste de soro-aglutinação em látex para diagnóstico do calazar canino.

Abstract

The aim of this work was to standardize a latex agglutination test for the diagnosis of canine kala-azar based on the detection of serum antibodies against the recombinant Leishmania HSP70 and to compare its performance with the commercially available ELISA S7. From a panel of 292 sera, 163 gave coincident results in both assays, 22 were positive in the latex test and negative in ELISA S7 and 94 were conversely positive in the latex assay and negative in ELISA S7. The latex text sensitivity was 68.12% (95% CI: 0.5579-0.7883), the specificity 55.24% (95% CI: 0.4824-0.6208), and the kappa value 0.173 (95% CI: 0,0740-0,2719), when the results were compared to those of ELISA S7. The conflicting results between the two tests are not within random expectation (p<0.0001 McNemar test). When the negative serum samples obtained in the standard serum dilution 1:2 were retested in higher dilutions, the sensitivity increased to 98.55%. The results suggest a promising potential for this new assay in the diagnosis of canine kala- azar, although some refinement is still needed, especially to increase the test specificity.