Allergy and Sensitivity Testing

IgE Testing (Immediate Reactivity, “True Allergy”)

True allergies are much easier to detect than food or chemical sensitivities. A true allergy is an acute or immediate reactivity, an Immunoglobulin E (IgE) immune mediated reaction. True allergies always trigger the release of chemicals called histamine or leukotrienes. A histamine reaction may cause a series of symptoms such as:

  • Rashes
  • Mouth sores
  • Itchiness
  • Swelling
  • Hives
  • Wheezing
  • The worst possible reaction: anaphylaxis – a potentially life-threatening allergic reaction

Usually most parents are aware of any true allergies their child may have because they already have a history of reactions that can’t be missed. This kind of testing is usually done with a skin scratch or skin prick test or via a blood test called a RAST test. You can talk to your pediatrician or allergist about this type of testing.

IgG and IgA Testing (Delayed Reactivity)

Testing for food and chemical sensitivities is much less obvious than those of true allergies because they are delayed and not immediate. Immunogobulin G (IgG) tests measure delayed immune reactions of foreign objects or undigested proteins that leak across the gut lining and into the blood stream causing a delayed immune response. Inflammation in the gastrointestinal lining causes the protective coating of antibodies called Immunogobulin A (IgA) to be released.

Both IgG and IgA tests search for antibody-antigen markers of foreign objects or specific undigested food proteins caused by Leaky Gut Syndrome (LGS). Symptoms of food and chemical sensitivities result from intestinal hyperpermeability (“leaky gut”) which is common to all autoimmune disorders.

Autism and other neurodevelopmental disorders are partly autoimmune disorders. Therefore, testing children with autism for food and chemical sensitivities and eliminating potential culprits from the diet may help with behaviors, language deficits, cognition and auditory and sensory processing.

Unfortunately, symptoms of food and chemical sensitivities are much more subtle and difficult to see; therefore, testing IgG and IgA or using another sensitivity test is extremely important for children with autism because of the possibility of unrecognizable long-term damage to the immune system.

Inflammatory Conditions

In Leaky Gut Syndrome, the mucosal lining of the gut can become inflamed. If severe enough, it can be very difficult for children with a leaky gut (especially children with autism) to find “safe” foods, or foods that won’t trigger a reaction from the immune system. Many children with a chronic health condition often have a inflammatory gastrointestinal mucosal condition such as:

In these children food and chemical sensitivity testing will often show large numbers of food and environmental sensitivities. In some cases, test results may indicate that as many as 60 or 80 foods may be causing inflammation for a particular child.

Eliminating a large portion of what your child eats may not be the best choice because this could contribute to further nutritional deficiencies. However, it is important to talk to an integrative health care practitioner or integrative dietitian to develop a strategy that will allow you to replace the worst food offenders with nutritious alternatives, or develop food-rotation strategies.


A well known test used to detect antibodies is a technique called ELISA (Enzyme-Linked Immunosorbent Assay). ELISA screens for both IgE and IgG reactions in a panel of about 100 food proteins including gluten and casein. Some labs will also test the subclass of ELISA: IgG4. IgG4 antibodies are associated with delayed food reactions that can worsen a condition. This test has been found to be an extremely helpful test for some children with autism.

Laboratory Testing

While laboratory testing for food reactions is available, it’s important to remember that results can vary widely from test to test, depending on the status of a person’s immune system and inflammation levels. A food that was deemed as “safe” may become inflammatory if it is relied upon too much, which is why it’s important to rotate foods and serve a wide variety of food. For these reasons, an elimination diet is seen as “the gold standard”.

Below are laboratories that offer tests to help you determine a course of action for your child:

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