Don’t order a Lyme immunoblot without a positive Lyme enzyme immunoassay screening test.
|Rationale and Comments:||The Lyme immunoblot test is designed only as a confirmatory test, so it is important not to test screen-negative samples. Some antigens on the blot react with non-Lyme antibodies, and the immunoblot can be overinterpreted in the absence of a positive screening test. Current two-tiered serology has a sensitivity of 70% to 100% and specificity > 95% for disseminated Lyme disease; use of an immunoblot without a positive screening test is unwise. While the exact characteristics of current immunoblot tests used alone are not well defined, high false-positive IgM rates have been observed in patients tested without a prior enzyme immunoassay. This recommendation assumes that a patient has had the potential for contact with ticks in an endemic area.|
|References:||• Moore A, Nelson C, Molins C, Mead P, Schriefer M. Current guidelines, common clinical pitfalls, and future directions for laboratory diagnosis of Lyme disease, United States. Emerg Infect Dis. 2016;22(7):1169-1177.
• Draft Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2019 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease.
• CDC Lyme Disease Resources: https://www.cdc.gov/lyme/index.html
• Wormser GP, Dattwyler RJ, Shapiro ED, et al. The clinical assessment, treatment, and prevention of lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2006;43(9):1089-1134.
• Seriburi V, Ndukwe N, Chang Z, Cox ME, Wormser GP. High frequency of false positive IgM immunoblots for Borrelia burgdorferi in clinical practice. Clin Microbiol Infect. 2012;18(12):1236-1240.