The Lyme Western Blot is a qualitative immunoassay in which antibodies specific to the B. burgdorferi antigens on a membrane strip are visualized. It is a qualitative test and is generally more sensitive and specific than the ELISA and IFA tests. In early or late stage of the disease when antibody levels are very low, western Blot can be positive whereas ELISA and IFA tests can be negative. This test must be used if the Lyme IgG/IgM antibody serology or Lyme IgG/IgA/IgM IFA is positive or equivocal.
Lyme Western Blot IgM
The Lyme Western Blot IgM is a very sensitive indicator of exposure to B. burgdorferi. It may be positive as early as 1 week after a tick bite. This test will usually remain positive for six to eight weeks after initial exposure and in some patients will remain positive for a very long time. Re-exposure will also cause this test to be positive for a brief period of time. For the testing to be complete, it is preferable that the IgM western blot be run along with the IgG western blot.
Reference Range
Negative <2 double started bands present on the blot
Clinical Significance
The Lyme Western Blot IgM is a sensitive indicator of exposure to B. burgdorferi. It may be positive as early as one week after a tick bite. This test will usually remain positive for six to eight weeks after initial exposure. Re-exposure will also cause this test to be positive for a brief period of time. In some patients this test can be positive for a very long time. Lyme Western Blot IgM must be performed on any sample with positive or equivocal result for Lyme IgG/IgM antibody serology or Lyme IgG/IgA/IgM IFA. For the testing to be complete, it is preferable that the IgM Western Blot be run along with the IgG Western Blot.
Sample Test Report
