disease. The purpose of this study was to determine the production of antibodies in a defined group of patients. Material and methods: The study analysed antibodies in the group of 25 patients with erythema migrans. For the detection of antibodies Immunofluorescence methods, ELISA and Western blot were used. Results: The detection of antibodies by Imunoflorescence methods proved positivity of the titre 1:256 in 14 patients and 9 patients were borderline, with the titre 1:128. Majority of the antibodies detected were of IgM class. The ELISA IgM test found positive reaction in 12 patients and 2 borderline results. IgG antibodies were found significantly more often by ELISA test than by Immunofluorescence. The Western blotting results were IgM positive in 9 patients, 6 were borderline. Only 5 patients have positive IgM results in all tests (Immunofluorescence, ELISA and at least one positive result out of three IgM Western blots). Discussion and conclusion: The tests which detect Borrelia burgdorferi antibodies are not standardized. They have variable sensitivity and specificity and their standardization is complicated with respect to great heterogenicity of Borrelia burgdorferi strains circulating in individual regions of Europe. The high specificity of antibodies to individual borrelia antigens are presently pointing towards the need to use, when in diagnostic confusion, more tests, which could detect antibodies also to other borrelia antigens (Tab. 3, Ref. 14). Full Text (Free, PDF) www.bmj.sk.