Comparison of immunofluorescence and enzyme linked immunosorbent assays for diagnosing Lyme disease

A new enzyme linked immunosorbent assay (ELISA) method was assessed in parallel with an indirect immunofluorescence assay (IFA) for the serological testing of specimens submitted for detection of Lyme disease. Wells of an ELISA microtitre plate were coated with sonicated whole cells of Borrelia burgdorferi in carbonate buffer. After overnight incubation at 4 degrees C the plates were washed three times, then incubated at 37 degrees C for an hour sequentially with a blocking solution, diluted test serum, anti-human IgG horseradish peroxidase conjugate, and finally for half an hour at room temperature with o-phenylenediamine substrate before being read at 492 nm. Absorbance results were converted into arbitrary ELISA units. Of a total of 1760 sera, 146 (8.3%) were positive: of these 92 (63%) were positive by both methods, five (3.4%) by IFA alone, and 49 (33.6%) by ELISA alone. The ELISA was better suited for testing large numbers of specimens and easier to interpret than IFA.