What is Borrelia burgdorferi IgG by Western Blot?
IgG antibodies to Borrelia burgdorferi sensu lato surface and flagellar proteins appear weeks to months after tick-borne infection and persist for years, even after treatment. Western blot separates serum immunoglobulins by protein molecular weight, transferring them to a membrane that is incubated with Borrelia lysate; reactivity to specific kilodalton bands reflects antibody recognition of distinct spirochaete antigens. The band pattern — not the absolute number of reactive bands alone — determines interpretation, and IgG responses are most reliable in late disseminated or chronic Lyme disease.