[Value of the immunosorbent agglutination assay (ISAGA) in the early diagnosis of congenital toxoplasmosis].

An IgM immunosorbent agglutination assay (ISAGA) test was evaluated for detection of IgM antibodies in diagnosis of congenital toxoplasma infection, and compared with IgM IFI test. Of 36 sera from infants with congenital infection, the IgM ISAGA test was positive in 19 cases (52%), whereas the IgM IFI test was positive in only 4 cases (11%). Of those sera obtained during the first 90 days of life from the infected infants, 70% were positive in the IgM ISAGA test whereas only 23% in the IgM IFI test. Neonatal sera from 10 infants suspected, but in whom this diagnosis was ruled out, were also evaluated: one false positive was found with the ISAGA test, but without control 15 days later. The ISAGA test is a simple, sensitive and probably highly specific test for diagnosis of congenital toxoplasma infection.