BACKGROUND: A decrease in the incidence of syphilis has been observed in the world and in Ukraine in recent years. At the same time, an increase in cases of neurosyphilis is recorded. Diagnosis of neurosyphilis is quite difficult and based on the correct interpretation of the complex of various diagnostic tests.

OBJECTIVES: The paper is aimed to determine diagnostic potential of treponemal tests (TTs) and evaluate effectiveness of Treponema pallidum immunoblot (TPI) while research on cerebrospinal fluid (CSF) in differential diagnosis of neurosyphilis.

MATERIALS AND METHODS: The research object was CSF of patients with late forms of syphilis. The regulated serological and immunological methods in accordance with current guidelines and orders of the Ministry of Healthcare of Ukraine were used for laboratory diagnosis of neurosyphilis: Enzyme immunoassays (EIA), fluorescent treponemal antibody (FTA), T. pallidum hemagglutination assay (TPHA), and TPI.

RESULTS: Effectiveness of TTs in the diagnosis of neurosyphilis while research on 23 samples of CSF was carried out by the following methods: EIA (Immunoglobulin [Ig]M + IgG), FTA, andTPHA. The above-mentioned TTs used in serological diagnosis of CSF do not always meet the problem of confirming neurosyphilis diagnosis. According to these investigations, both positive and false positive results were obtained. In order to verify the diagnosis, a study on positive and false positive samples of CSF by TPI method was carried out. Positive results were obtained in 13 samples with the established duration of the disease.

CONCLUSIONS: TPI is an optimal treponemal immunological method of examination of CSF to diagnose neurosyphilis with a high degree of reliability. The use of TPI while research on CSF makes it possible to verify the diagnosis of neurosyphilis by differentiated detection of antibodies to the most immunogenic antigens of T. pallidum eliminating the subjective factor of the reaction and simplifies diagnostic procedure.