Lyme disease (LD) is caused by spirochetal bacteria from the genus Borrelia. Borrelia burgdorferi is the predominant cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii are predominantly implicated in most European incidences. The CDC estimates roughly 30,000 confirmed cases of LD in the U.S. per year since 2008, but suggests the number may be closer to 300,000. Each year 2.5 million serological LD assays are performed, many of which are repeat tests. The recommendations by the CDC for the diagnosis of LD include a two-tiered approach: an initial ELISA-based screening test in conjunction with Western blotting to establish the presence of anti-Borrelia antibodies.