Lyme Disease: Serologic Assays for Antibodies to Borrelia burgdorferi

Lyme disease is the most common tick-borne bacterial disease in the northern hemisphere. The disease is caused by three genomic groups or genospecies of Borrelia burgdorferi sensu lato: B. burgdorferi sensu stricto, B. garinii, and B. afzelii. Only B. burgdorferi sensu stricto is known to cause Lyme disease in North America, whereas all three genospecies are responsible for the disease in Europe. Serology is the most useful type of laboratory test that is widely available to support a clinical diagnosis of Lyme disease. Positive serologic test results, however, should not be used by themselves to establish this diagnosis. Laboratory testing of samples from such patients also is not recommended, since testing will result in more false-positive results than true positives. Serum specimens first should be evaluated by a sensitive enzyme immunoassay (EIA) or immunofluorescent assay (IFA). During the first month of infection, both immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody responses should be determined. A strain used as an antigen in a serologic test should express appropriate amounts of the immunoreactive proteins of diagnostic interest. Positive-control serum samples from patients with well-characterized Lyme disease are required, preferably four samples that possess a range of anti-B. burgdorferi antibody levels from low to high.