When should IgG be retested?

The appropriate timing for IgG retesting depends entirely on the clinical context. For IgG food sensitivity tests (often IgG4), current guidelines from allergy societies (e.g., EAACI, ACAAI) strongly advise against their use because they detect normal immune responses to food, not allergies or intolerances. Retesting such markers is not evidence-based and may lead to unnecessary dietary restrictions. In contrast, for IgG antibodies against infectious agents (e.g., Lyme disease, EBV), retesting may be indicated to monitor seroconversion or treatment response, typically 4–6 weeks after initial testing or after therapy. However, without a specific clinical question, repeat IgG testing is rarely useful. The provided context does not include any relevant data on IgG retesting; this answer reflects general medical consensus. Caveat: consumer IgG tests are often marketed with weak evidence; always interpret results in a clinical setting.