Controversial Tests And Treatments

There are some questionable practices for diagnosis and treatment of food allergies. Tests that are not scientifically valid and are considered experimental include:

• Blood tests that determine food immune complexes and IgG food antibodies: Such tests measure substances that all normal people have in their blood. Food immune complexes form after food digestion. IgG includes most of the protective antibodies, including those that form when you receive a vaccine or after an infection. It is unclear whether people with allergies make abnormal amounts of these substances.

• Cytotoxic test: This test involves adding a food allergen to someone's blood sample and examining the reaction of white blood cells under a microscope. If the cells change shape, decrease or die, the person is thought to be allergic to that food. No proof exists that this test is effective for diagnosing food allergy.

• Provocation and neutralization: In the subcutaneous (under the skin) form of this test, a food extract is injected under the skin. In the sublingual (under the tongue) form, the food extract is placed under the person's tongue. If the person has an allergic reaction, he or she receives more of the substance. The belief is that the second dose neutralizes, or relieves, the symptoms. In reality, it can cause a severe allergic reaction.

  Some doctors use provocation and neutralization to try to desensitize allergic people to foods. But the technique has been found to be ineffective for both diagnosis and treatment of allergies.