DETERMINATION OF ANTI TOXOPLASMA-GONDII IMMUNOGLOBULIN-G AVIDITY - ADAPTATION TO THE VIDAS SYSTEM (BIOMERIEUX)

The determination of specific anti-Toxoplasma gondii IgG avidity has b een proposed to improve the determination of the date of toxoplasmic s eroconversion in pregnant women. In this study, we adapted this serolo gical technique to the Vidas system (bioMerieux) using 6 M urea as the dissociating agent. We studied 356 sera, including 42 sequential sera from seroconversions in pregnant women. Our results show that the tes t is easy to use, and that an avidity index higher than 0.300 allows t he exclusion of a recent infection acquired less than 4 months before serum sampling. (C) 1998 Elsevier Science Inc.