February 13, 2015
IgG 18 is an antibody band that is sometimes seen reported on the Western Blot test performed in patients with Lyme disease.
The interpretation of the presence of this band on a report has been one of contention. Under the tremendously controversial CDC surveillance guidelines, the presence of IgG 18 must be accompanied by the presence of at least four other bands for a diagnosis of Borrelia infection to be made.
However, many experienced clinicians believe that the IgG 18 band alone is sufficient to support a diagnosis of Lyme disease.