IgG Borrelia afzelii
The IgG Borrelia afzelii test measures antibodies against Borrelia afzelii, one of the main bacterial species that cause Lyme disease in Europe and Asia. Unlike Borrelia burgdorferi (more common in North America), B. afzelii is especially associated with chronic skin forms of Lyme disease, such as acrodermatitis chronica atrophicans (ACA).
What IgG B. afzelii Means
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IgG antibodies generally appear weeks to months after infection and often persist long-term, even after treatment.
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A positive IgG B. afzelii result suggests past exposure or ongoing immune memory to the bacteria, which may help clinicians determine whether symptoms are linked to later or chronic stages of Lyme disease.
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In contrast, IgM antibodies are more indicative of recent infection, so IgG testing provides a complementary view of the immune timeline.
Clinical Importance
Testing for IgG B. afzelii can be helpful in patients with:
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Persistent or late-stage Lyme symptoms, particularly skin changes such as ACA
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Neurological or musculoskeletal issues suspected to be related to European Lyme disease strains
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A history of tick exposure in endemic regions of Europe or Asia
Patient Takeaway
A positive IgG B. afzelii result indicates that your immune system has previously recognized this strain of Borrelia. This does not always mean there is an active infection, since IgG can remain detectable for years. Your healthcare provider will interpret the result in the context of your symptoms, exposure history, and other Lyme disease tests.
IgG B. afzelii
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