Myths vs facts: IgG and Allergie

A common myth is that IgG (Immunoglobulin G) tests can reliably diagnose food allergies or intolerances. In reality, IgG is a memory antibody produced after normal food exposure – its presence simply indicates the body has encountered that food, not that it triggers an allergic reaction. True allergies are mediated by IgE (Immunoglobulin E), which causes acute symptoms like hives, anaphylaxis, or asthma. Major allergy societies (e.g., EAACI, AAAAI) strongly advise against using IgG tests for allergy diagnosis because they yield many false positives and lead to unnecessary dietary restrictions. Some labs market IgG tests for 'delayed allergies,' but this concept lacks scientific validation. The German Society for Allergology (DGAKI) also classifies these tests as not recommended. Bottom line: IgG testing is not a valid tool for diagnosing food allergies or intolerances. If a food allergy is suspected, a specialist should perform IgE-based diagnostics (e.g., skin prick test, specific IgE blood test). The evidence is human-strong, based on clinical guidelines and systematic reviews.