Standardized serologic tests for
Lyme disease are needed, as isolation or in situ demonstration of the spirochete has proved difficult. At the Centers for
Disease Control (CDC), an indirect immunofluorescence assay (IFA) was modified from a previously described IFA, and an enzyme-linked immunosorbent assay (ELISA) was developed with soluble spirochetal antigens. Both tests were evaluated with sera from
Lyme disease patients, normal controls, and patients with other diseases. They were highly specific for
Lyme disease when sera from patients with syphilis were excluded. Sensitivity varied with
disease stage: for patients with erythema chronicum migrans alone, the IFA was 53 percent sensitive and the ELISA was 67 percent sensitive. In contrast, all patients with complicated
Lyme disease had at least one serum specimen positive in both tests. Twenty-six percent of the sera from 289 patients with suspected
Lyme disease that were submitted to CDC in 1983 had IFA titers greater than or equal to 256 and thus were considered positive. Both tests should be useful diagnostic and epidemiologic aids.