Antigens to detect the acute phase of toxoplasmosis in pregnant women: standardized comparison.

A key element in any diagnostic technique is the antigen (Ag), a biomarker, but this is usually a protein that has a function to the parasite. Some biological aspects of the Ags and of the Toxoplasma gondii can influence the effectiveness of the diagnosis, as well as the antibody isotype and the characteristics of the assay. A large number of papers have assessed different proteins to distinguish the phases of infection, but the 'indices of effectiveness' differ among reports. This work presents for the first time a summary of all the Ags that have been evaluated, with standardized measurements of sensitivity and specificity. These values were calculated with information presented in the papers on Ag evaluations to differentiate the infection phases.