IgG (Immunoglobulin G) is a type of antibody that reflects the body’s long-term immune response. It is the most abundant antibody in the blood and plays a key role in defending against infections. In the context of Lyme disease, caused by the bacterium Borrelia burgdorferi, IgG antibodies are measured to evaluate past exposure or later stages of infection. Unlike IgM antibodies, which appear early, IgG antibodies develop more gradually and can persist in the body for extended periods, providing lasting immunity.
IgG testing is crucial for detecting later stages or past exposure to Lyme disease. IgG antibodies to Borrelia burgdorferi typically develop several weeks to months after initial infection and can persist for years, making this test useful for identifying chronic or previous infections.
Individuals with long-term symptoms that suggest Lyme disease, such as chronic joint pain, neurological symptoms, and fatigue, should consider IgG testing. It is also recommended for those who have had a previous positive Lyme disease test or who have been treated for Lyme disease in the past.
The test involves analyzing a blood sample for the presence and concentration of IgG antibodies specific to Borrelia burgdorferi. Higher levels of these antibodies suggest a later stage or a past infection.
IgG and IgM antibodies serve different roles in the immune response to Lyme disease. IgM antibodies appear first, within a few weeks of infection, indicating recent exposure. IgG antibodies develop later, remain longer, and indicate past exposure or ongoing infection. Testing for both types of antibodies at different stages can provide a more complete picture of the infection timeline.