Can IgG help with allergy?

Whether IgG testing helps with allergies is scientifically controversial. IgG antibodies in blood merely indicate immune exposure to a food, not necessarily an allergy or intolerance. Major allergy societies (e.g., EAACI, AAAAI) advise against IgG-based tests for diagnosing food allergies because they often yield false positives and lead to unnecessary dietary restrictions. True allergies are mediated by IgE antibodies and require medical diagnostics (skin prick test, IgE measurement, possibly oral challenge). IgG tests are frequently marketed as 'food sensitivity tests,' but evidence for clinical benefit is weak. In practice, they can even cause harm if patients eliminate important foods based on misleading results. In summary: IgG does not help in allergy assessment; rely on IgE-based methods and medical guidance.