Serologic tests for Lyme disease. Interlaboratory variability.

The serologic test for the detection of antibodies to Borrelia burgdorferi is the most frequently used laboratory method for the diagnosis of Lyme disease. However, the insensitivity of the assays and the interlaboratory variability are frequent problems. To determine the extent of this variability, one aliquot of serum from each of nine patients with a history of Lyme disease was sent to nine reference laboratories, including national, university, state, and local hospital laboratories. A second aliquot of the original serum was submitted 2 weeks later. Wide variability among laboratories was observed, ranging from a university laboratory that detected antibody to B burgdorferi (IgG or IgM) in 18 of 18 specimens, to a state laboratory that detected antibody in only 8 of 18 specimens. Detection of IgM specific antibodies showed similar variability (range, 2 to 10 of 18). There were eight instances of a fourfold or greater change in titer between the aliquots sent 2 weeks apart, although only three of these were an increase in titer. These results indicate the need for standardization of the assays and the availability of national reference material. It is recommended that the results of serologic testing should not be relied on as the sole criteria in making the diagnosis of Lyme disease.