Cautions

The immunoblot result may be negative in specimens that are weakly positive by enzyme immunoassay or in patients with early Lyme disease.

Test results should be used in conjunction with clinical evaluation and information related to tick exposure.

A negative test result does not necessarily rule out current or recent infection. The specimen may have been collected before demonstrable antibody developed. Patients with early disease often have serum antibody levels below the diagnostic threshold for several weeks following disease onset.

Test results from pregnant women or patients who are immunosuppressed may be difficult to interpret.

Positive test results may not be valid in persons who have received blood or blood product transfusions within the past several months.

Antibiotic therapy administered early following exposure or disease onset may suppress the antibody response to the point that diagnostic threshold levels are never attained.

Lyme disease serology should not be used for monitoring treatment response, as IgG can remain detectable for years post-resolution of infection.

Epitopes from certain B burgdorferi proteins (eg, p41) are conserved across other bacteria, which may lead to the detection of IgM- and/or IgG-class antibodies on the Lyme disease immunoblots in patients without Lyme disease.

Immunoblot testing should only be ordered on specimens that are positive or equivocal by a US Food and Drug Administration-licensed Lyme disease antibody screening test (eg, enzyme immunoassay).

Results of the Lyme IgM immunoblot should not be considered in patients with greater than or equal to 30 days of symptoms.

False-positive reactions may occur with patients with other spirochetal diseases (syphilis, yaws, pinta, relapsing fever, or leptospirosis), recent Epstein-Barr virus infection (ie, infectious mononucleosis), influenza, autoimmune disorders (eg, present of extractable nuclear antigens), multiple sclerosis, or amyotrophic lateral sclerosis.