Evaluation of a two-test serodiagnostic method for community assessment of Lyme disease in an endemic area.

Epidemiological methods are needed to evaluate community exposure to Borrelia burgdorferi, the causative agent of Lyme disease (LD). For LD serodiagnosis, the Centers for Disease Control and Prevention (CDC) recommends a 2-test approach that involves enzyme immunoassay (EIA) testing and Western immunoblotting (WB) of EIA-equivocal and EIA-positive specimens. The specificity of this approach was evaluated among residents of a LD-endemic community and was compared with WB alone and with a simplified 2-test approach (WB of equivocal EIA only). Participants reporting no previous diagnosis of LD were recruited during a community-wide serosurvey on Block Island, Rhode Island. Of 80 eligible participants, 20 had received LD vaccine. Seven (35%) of 20 vaccinees and 22 (37%) of 60 nonvaccinees reported nonspecific symptoms compatible with LD in the previous year. In this highly LD-endemic community, the overall specificity of the CDC-recommended approach was highest (100%), followed by WB alone (98.7%), then the simplified approach (95%).