Comparison of a commercial enzyme immunoassay and an immunoblot technique for detection of immunoglobulin A antibodies to Toxoplasma gondii.

A commercial enzyme immunoassay (Platelia-Toxo IgA) and an immunoblot technique were compared with regard to their ability to detect IgA antibodies to the major surface protein P30(SAG1) of Toxoplasma gondii in 105 serum samples from patients with suspected or proven acquired toxoplasmosis. Comparison of the IgA-EIA with the immunoblot technique showed a concordance of 81.0%, with a sensitivity of 92.6% and a specificity of 78.4%. Due to its high sensitivity the IgA-EIA might detect IgA antibodies against Toxoplasma gondii at an early stage of infection, although excessive sensitivity could lead to detection of IgA antibodies for an extended period of time following the onset of infection.