Is IgG useful for blood sugar?

Is IgG testing useful for blood sugar? The short answer is no. IgG food sensitivity tests are marketed directly to consumers, but they lack scientific validation for diagnosing food intolerances or guiding metabolic health. Medical guidelines from organizations like the European Academy of Allergy and Clinical Immunology (EAACI) explicitly advise against using IgG tests for food intolerance diagnosis due to high false-positive rates and lack of clinical correlation. Blood sugar regulation depends on insulin sensitivity, glucose metabolism, dietary carbohydrate intake, physical activity, and genetic factors—not on IgG antibody responses to foods. While some companies claim that eliminating foods identified by IgG tests can improve blood sugar, no robust clinical evidence supports this. In fact, unnecessary dietary restrictions may lead to nutrient deficiencies or disordered eating. For individuals concerned about blood sugar, validated tools such as HbA1c, fasting glucose, oral glucose tolerance tests, or continuous glucose monitors are appropriate. IgG testing is not a recognized tool in diabetes or prediabetes management. Therefore, consumers should be cautious: the evidence level for IgG tests in this context is best described as 'marketing' rather than evidence-based medicine.