[Relevance of the new test Access Toxo IgM (II) in the serological interpretation of toxoplasmosis in pregnancy]. / Intérêt du nouveau test Access Toxo IgM (II) dans l'interprétation sérologique de la toxoplasmose au cours de la grossesse.

ABSTRACT

The detection of specific IgM is an important element in the diagnosis of seroconversion. In this study, we compared the new test Access Toxo IgM (II) versus the previous test Access Toxo IgM (I). This comparative study was done with 507 random sera and 89 selected sera (seroconversion, residual IgM, non specific IgM). The sensitivity and the specificity are higher with the new test (100% & 100% versus 97% & 98,6% respectively). Then, the high sensitivity of Access Toxo IgM (II) is more convenient for the earlier diagnosis of primary Toxoplasma infection. Moreover, the Access Toxo IgM (II) test was evaluated with our first results in routine laboratory (11,000 serology results between June 2000 and June 2001). With these results, we can confirm the specificity of the new test, and also determine the relevance of anti-toxoplasmic IgM. Moreover, an increase of sensitivity leads to an increase of residual IgM detection 64% (37/58) of positive IgM is residual (> 4 months) as compared to 35% (27/78) with the previous test. In these case, the initiation of other tests such as the avidity test is necessary to validate or invalidate a seroconversion during pregnancy.