There are various serodiagnostic tests available for the detection of antibodies against Borrelia burgdorferi. An indirect hemagglutination assay, which can detect both IgM and IgG antibodies, was developed for antibody screening. Regarding the confirmation and differentiation of IgM and IgG, we use the indirect immunofluorescence assay (most specific when performed with sera previously absorbed with Treponema phagedenis) as well as the ELISA test. The detection of significantly elevated antibody titers depends on the stage of the
disease. In erythema migrans, only 20-50% of the patients are seropositive (with a prevalence of IgM); in neuroborreliosis, the figures amount to 70-90% of the patients (prevalence of IgM in early stages and IgG in advanced stages); and 90-100% of the cases with acrodermatitis and arthritis show elevated titers of IgG (IgM antibodies usually are not detectable in late manifestations). The clinical manifestations of the
disease is serologically marked by IgM antibodies or–in neuroborreliosis–by intrathecal production or antibodies which can be detected on account of an increased CSF/serum index.