Lyme Disease Antibody
Last updated: October 9, 2014
Description: A serologic test that may be used to confirm the diagnosis of Lyme disease.
Method: Screening for serum antibodies against Borrelia burgdorferi is done using ELISA or, less commonly, an indirect immunofluorescent assay. Additional specificity is provided by Western immunoblot confirmation (more than three bands is considered confirmatory). PCR has been used to confirm B. burgdorferi DNA in ticks but is not yet standardized for routine clinical use in humans.
Normal Values: This test is normally negative.
Increased in: Specific IgM antibody peaks within 3 to 6 weeks after Lyme disease onset. IgG titers increase more slowly and are often present when arthritis begins. CSF antibody levels help confirm neuroborreliosis.
Confounding Factors: Serology may be normal in early disease or with an attenuated immune response to a partially treated infection. Cross-reactivity with other spirochetes such as Treponema pallidum can lead to false-positive results. False positives also occur in <20% of patients with high-titer RF. High serum lipid levels and hemolysis may interfere with results.
Indications: Serologic testing should only be done when individuals are strongly suspected of having Lyme disease because of (a) the low prevalence of Lyme disease in nonendemic areas; (b) significant false-positive and false-negative rates; and (c) considerable intra- and interlaboratory variation in results.
Cost: Enzyme immunoassay, $75–110; Western blot, $120–160; PCR, $130–180.
Comments: Lyme disease remains a clinical diagnosis with laboratory studies helpful for confirmation. Half of patients with early Lyme disease (erythema chronicum migrans, constitutional features), and nearly all those with late Lyme disease (carditis, neuritis, arthritis) or in remission have positive serologic test results.
