What is the difference between IgE and IgG4 tests?

IgE and IgG4 tests measure different types of antibodies and serve distinct purposes in allergy diagnosis. IgE tests measure Immunoglobulin E antibodies, associated with immediate allergic reactions. IgG4 tests measure Immunoglobulin G4 antibodies, which are typically associated with tolerance or desensitization to allergens. IgG4 tests are not used for diagnosing allergies but may be involved in the process of developing tolerance to allergens through allergen immunotherapy. IgE tests are specific to identifying immediate-type allergic reactions and are the primary tests used for allergy diagnosis.