La sierodiagnosi della toxoplasmosi nella gravida e nel neonato: esperienze dell'unità operativa dell'Azienda Sanitaria di Bolzano (Laboratorio di Microbiologia e Virologia)

Serodiagnosis of T. gondii infection is difficult because the disease can manifest in several possible ways and because of the particolar dynamic of anticorpal response.The resulting interpretation problems entail prognostic, therapeutic and ethical difficulties in the case of pregnant women and their children.The resolution of these problems goes through an extremly articulate path: the information provided by screening tests intersects with results of supplementary assays and can be enriched thanks to complementary markers (IgA) and second-level tests (IgGavidity). Each laboratory must be able to choose and to combine complementary investigation methods and to plan an adequately diagnostic strategy. Sera arriving to our laboratory undergo screening by enzyme immunoassays Axsym Toxo IgG/IgM (Abbott). Subsequently confirmation of positive, weak positive and doubtful results is entrusted to the assays VIDAS Toxo IgGII/IgM (bioMerieux), and in case of newborns to the assay ETI-TOXO-MReverse Plus (diaSorin). IgA antibodies are determined by immunoassay ETI-TOXO-A-Reverse Plus (diaSorin); the IgG-avidity is evaluated by test Toxo-IgG-avidity (bioMerieux). Analysis of toxoplasma infections occured during pregnancyas resulting by a 3 years survey period, shows that combined use of our assays contribuites to a correct diagnosis. The contribution obtained by the comparison of evaluation IgGAxsym/IgG VIDAS, provides very useful clues to evaluate the infection degree in advances with respect to evaluation of IgG-avidity.