Role of Toxoplasma IgA as part of a Reference Panel for the Diagnosis of Acute Toxoplasmosis During Pregnancy. Journal of clinical microbiology Olariu, T. R., Blackburn, B. G., Press, C., Talucod, J., Remington, J. S., Montoya, J. G. 2018

Abstract

This study evaluated the usefulness of adding the Toxoplasma gondii IgA antibody ELISA test to the serologic panel of tests done for the diagnosis of acute toxoplasmosis in pregnant women in a reference laboratory in the United States. We conducted a retrospective study of 690 consecutive pregnant women with positive T. gondii IgG antibody test results who also had T. gondii IgA and IgM antibody tests performed. Patients were defined as acutely or chronically infected with T. gondii based on a panel of serologic tests performed at the Palo Alto Medical Foundation - Toxoplasma Serology Laboratory (PAMF-TSL). Among the 81 women who were positive by T. gondii IgA antibody ELISA testing, 61 (75.3%) were acutely infected with T. gondii, while of the 547 who were negative by IgA testing, only 24 (4.4%) were acutely infected (p<0.001). Among the 71 women who were positive by both IgA and IgM antibody tests, 61 (85.9%) were acutely infected, compared to 24 (19.2%) of the 125 women who were positive by only the IgM ELISA (p<0.001). These results demonstrate that pregnant women with T. gondii IgA antibodies are more likely to have had a recent infection with T. gondii compared to pregnant women without T. gondii IgA antibodies. Toxoplasma IgA antibody testing can therefore improve the accuracy of a serologic panel for the diagnosis of acute toxoplasmosis during pregnancy. Physicians who ordered testing only for T. gondii IgG and IgM should also request additional testing for IgA and IgG avidity, if both IgG and IgM are positive. This further testing should be ideally performed in a reference laboratory.

View details for PubMedID 30463899