FIELD: medicine. SUBSTANCE: method involves taking blood serum in the amount of 5-10 ml at the tenth-fourteenth day from the beginning of disease exacerbation from patients suffering from chronic toxoplasmosis form during the period of 2-10 years . The samples having titer ≥ 1:640 in applying indirect immunofluorescent antibodies method or titer ≥ 1:3200 in applying immunofluorescent antibodies method are inactivated at 56 C during 30 min. Then immunoglobulin fraction is separated by means of double precipitation with 20% ethylene glycol solution of type 6000. It is labeled with fluorescein-5-isothiocyanate in Ig: fluorescein- 5- isothiocyanate proportion being equal to 20:1. EFFECT: enhanced effectiveness in producing immunofluorescent antibodies of high activity level; high accuracy in detecting Toxoplasma in materials containing admixtures. 1 tbl
