What do studies say about IgG Unverträglichkeit Test?

The IgG food intolerance test is often marketed to detect 'delayed' food sensitivities. However, the scientific evidence is weak: elevated IgG levels typically reflect normal immune exposure (e.g., after eating a food) rather than a pathological reaction. Clinical guidelines (e.g., from the European Academy of Allergy and Clinical Immunology) advise against IgG-based tests for diagnosing food intolerances, as they are not validated and may lead to unnecessary dietary restrictions. While some studies have explored links between IgG and conditions like irritable bowel syndrome, results are inconsistent and methodologically limited. Therefore, evidence-based medicine does not recommend these tests. For genuine intolerances (e.g., lactose, fructose, histamine) or allergies (IgE-mediated), validated methods such as breath tests, elimination diets, or specific IgE diagnostics should be used. The IgG test remains a marketing tool without solid clinical backing.