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

Epidemiological methods are needed to evaluate community exposure to Borrel ia burgdorferi, the causative agent of Lyme disease (LD). For LD serodiagno sis, the Centers for Disease Control and Prevention (CDC) recommends a 2-te st approach that involves enzyme immunoassay (EIA) testing and Western immu noblotting (WB) of EIA-equivocal and EIA-positive specimens. The specificit y 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 we re recruited during a community-wide serosurvey on Block Island, Rhode Isla nd. 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 communi ty, the overall specificity of the CDC-recommended approach was highest (10 0%), followed by WB alone (98.7%), then the simplified approach (95%).