The sensitivity of the IgG4 ELISAs based on Onchocerca volvulus adult worm antigen (OvAg) (left panel) and on the O. volvulus-specific recombinant antigen Ov16 (right panel) for the detection of patent O. volvulus infection (Mf positivity).

The contingency table indicates, in the upper left and right panels, the percentage of false-negative results in relation to Mf positive test results. In the lower left and right panels, the percentage of correct positive results in relation to Mf positivity is highlighted for the OvAg-IgG4 and Ov16-IgG4 ELISAs. The cutoff for IgG4-OvAg and IgG4-Ov16 positive responses was set at the upper limit of the 95% confidence interval of the mean optical density (OD) in O. volvulus microfilariae (Mf) negative 5–10 year old children.