Efficient duplex solid-phase fluorescent assay (dFISA) for the simultaneous detection of specific anti-T. gondii IgG...

Toxoplasma gondii infections are very common, causing occasional central nervous system and eye diseases, and must be screened in prenatal care for efficient therapy. Here, we developed a duplex solid-phase fluorescent assay (dFISA) for the simultaneous detection of anti-T. gondii IgG and IgM antibodies in prenatal care screening for toxoplasmosis. Assays using commercially available ion-exchange purified conjugates yielded poor results and high background fluorescence. Same-well IgG/IgM dFISA with refined conjugates was used to test 140 samples from university students, 120 samples from pregnant women and 24 samples from adult volunteers at a large public hospital. We found that dFISA offers high concordance, specificity and reproducibility for IgG (Kappa=0.883) and IgM (Kappa=0.918), which is useful in high-throughput applications for antenatal care.