Detection of anti-Leishmania antibodies in blood collected on filter paper by the direct agglutination test.

Human capillary blood drawn by finger pricking was absorbed on Whatman no. 4 filter paper and tested for anti-Leishmania antibodies using the direct agglutination test (DAT). Over 1400 filter paper samples were collected from L. infantum endemic areas in northern Pakistan and compared with 569 serum samples obtained from the same area. Eleven filter paper samples (0.8%) gave positive results (antibody titre > or = 1:3200), compared with 8 serum samples (1.4%); the difference was not statistically significant (P = 0.35). The filter paper eluates compared well with their homologous sera, and were strongly correlated with respect to antibody titre (r = 0.7, P < 0.0001).