Serodiagnosis of ocular toxocariasis: a comparison of two antigens

This study was designed to compare the sensitivity and specificity of enzyme linked immunosorbent assay (ELISA) for the serodiagnosis of ocular toxocariasis using Toxocara canis embryonated egg antigen (TEE) and toxocara excretory-secretory or exoantigen (TEX) produced in vitro. TEE and TEX ELISA were comparably sensitive, but TEX ELISA was better able to discriminate between serum samples from patients with ocular toxocariasis and those from patients with retinoblastoma. In addition, preabsorption of sera with Ascaris suum embryonated egg antigen seemed to be essential to prevent false positive results with TEE ELISA but was not so critical for TEX-ELISA. Further studies are still required to standardise TEX for serodiagnosis.