[Combining indirect hemagglutination with the direct agglutination as a parameter for evaluating patients sent for serological verification of toxoplasmosis].

Abstract

The importance that Toxoplasma gondii congenital infection may assume is still representing a stimulus for trying to improve Toxoplasmosis serological diagnosis; task, this one, which Laboratory is charged with, and that is often hard, particularly when we have to value the possibility of an infection in progress. With the purpose to complete the results obtained in a preceding work of ours, we have valued two among the most commonly used tests for Toxoplasmosis serodiagnosis, the AD (direct agglutination provided by BioMerieux) and the IHA (indirect haemoagglutination provided by Behring), together and separately, in order to make use of their coupling with major security and effectiveness, on the ground of the results obtained on two different groups of individuals, in the number of 125 for each group; for these groups it was possible to expect a different index of receptivity and a different percentage of recent or in progress infections. It was come out, as regards the IHAm a very good degree of assurance in trying to single out the past immunity, while this test wouldn't generally seem to be able to offer sufficient indications to distinguish the recent or in progress infection from past immunity, as it often declares, in fact, middle-high titres also in cases probably referable to the last mentioned situation. The AD has offered a good tribute in estimating the past immunity and it would also appear to give assurance in singling out recent or in progress infection (thanks to the possibility to determine IgM presence); while the presumed capacity of this test in revealing cases of very early infection has resulted not sufficiently assured. In substance the coupling of the two test, which in the direct comparison have shown a good correlation, but also several discordances, seems to be an useful procedure of reciprocal confirmation as regards the singling out of immunity; while the possibility of showing the recent or in progress infection--anyway, always a difficult task, above all, when, as it happened in this research, we deal with it without being able to follow the titre evolution in the time-should be entrusted with major certainty to the AD.