The methods of immune enzyme assay (MIEA) and of lanthanide immunofluorescence analysis (LIFA) were used to work out the test systems for the detection (in blood serum of patients) of specific IgM IgG antibodies to the B. burgdorferi spirochete–a causative agent of ixodic borrelioses. The test system was clinically tested versus the indirect immunofluorescence reaction (IIFR) and commercial immune enzyme test system (CIET). The results of antibodies’ detection were shown to correlate with the analysis data for the same sera in IIFR and to be in line with a real presence or absence of the
disease. Test systems based on LIFA were proven to be most sensitive and specific.