Validity of prior absorption of serum samples with Reiter's spirochetes in serological diagnosis of Borrelia burgdorferi infections.

Evidence of Borrelia burgdorferi sensu lato infection was sought in 230 patients with positive antibody titres in an indirect immunofluorescence test that became negative after serum samples were preabsorbed with treponemal antigen. Infection could be excluded in 82.2% (189/230) of patients, was questionable in 6.9% (16/230), and was judged to have occurred in 10.9% (25/230), including four (1.7%) cases of early, acute disease that required treatment. The preabsorption procedure clearly reduces the frequency of false-positive reactions; however, there is a definite risk of overlooking active infections with this technique.