Toxoplasmosis in pregnant women from Araraquara/SP: Analysis of Toxoplasma-specific IgG avidity test utilization in the prenatal care routine

Aims: To evaluate the utilization of Toxoplasma gondii (T. gondii) IgG avidity test in the laboratory routine of prenatal care in pregnant women from Araraquara/SP and to analyse its relationship with the antiparasitic treatment and the occurrence of congenital toxoplasmosis. Methods: From January to November 2005, at the Laboratorio de Imunologia Clinica e Biologia Molecular do Centro de Referencia Diagnostica do Nucleo de Atendimento a Comunidade da Universidade Auxiliar Integrada a Faculdade de Ciencias Farmaceuticas, Campus de Araraquara, UNESP, Araraquara/SP, the results of the serological tests for toxoplasmosis in the prenatal care routine were analyzed in two groups of patients. One consisting of pregnant women with negative T. gondii-specific IgM (n=200) and the other consisting of pregnant women with positive T. gondii-specific IgM (n=33). The T. gondii-specific IgG avidity test was performed in the group with positive T. gondii-specific IgM. Results: Most pregnant women (76.9%) who presented intermediate avidity test results received antiparasitic treatment. Of the 16 pregnant women who presented high avidity results, nine (56,25%) received antiparasitic treatment. Conclusions: Even in the presence of a high specific-T. gondii IgG avidity test in the first trimester of gestation, the antiparasitic treatment was instituted, demonstrating that the avidity test was not adequately utilized in the clinical practice.