The diagnosis of toxoplasmosis is mainly based on the research and quantification of specific antibodies (IgM and IgG) by indirect immunofluorescence ( IFA ) or immunoenzymatic assay ( EIA ).
The anti-toxoplasma IgM appear during the first 2 weeks of acute illness, with a peak between the fourth and eighth week, before becoming indeterminable (only in certain cases, can be found up to the 18th month after infection) . Specific IgGs, on the other hand, are formed more slowly, peak in 1-2 months and can remain high and stable for months or years. In a healthy subject, the previous infection produces a negative Toxo test for IgM and a positive IgG.
The presence of Toxoplasma gondii can be demonstrated by histological examinations, culture and PCR for parasite DNA on tissue samples and organic fluids (blood, CSF and amniotic fluid). In addition to these tests, some targeted instrumental investigations, such as computerized tomography, magnetic resonance imaging, ultrasound and ophthalmoscopy, may help confirm the suspicion of toxoplasmosis.
