IgE Versus Non-IgE Allergy Testing

Posted 4.13.12 | Nutrition Specialist

Many Neocate parents know that using allergy testing to determine food allergies can be tricky, because many children experience what may be considered a food intolerance or sensitivity, versus a true food allergy. 

Generally, a food allergy is considered to be an immunoglobulin E (IgE) mediated immune response.  (1) In a previous blog, we have outlined the standard tests that may be done to determine whether your child has an Ig-E mediated food allergy, such as a skin prick test or a RAST.

However, you or your child may have a negative IgE test, but still appear to have symptoms that are typical of a food intolerance or sensitivity.  Several tests are now marketed as tools for determining these types of non-IgE mediated food reactions.  While more research is needed to determine the accuracy of these tests, they may provide helpful clues as to which foods to consider eliminating from the diet. Some of these tests include:

Enzyme Linked Immunosorbent Assay (ELISA): A blood test that is intended to measure levels of immunoglubulin G (IgG) in response to different foods.  However, elevated IgG does not always indicate an adverse food reaction.  In fact, sometimes elevated IgG is an indicator that an IgE response, or a true allergy, has been successfully treated.  This test may be helpful in providing clues as to which foods to consider eliminating, but remember that elevated IgG does not always mean that there is a negative reaction to the food.  (2, 3)

Mediator Release Testing (MRT): A blood test that in intended to measure many types of non-Ig-E mediated food intolerances or sensitivities, including IgG response.  Proponents of MRT believe that because it assesses multiple immune pathways it provides a more complete picture of which foods are causing symptoms compared to IgG testing.  (3)

Atopy Patch Testing (APT): A skin test used to determine delayed food reactions.  A preparation of the food is placed in an aluminum chamber on the skin for 48 hours. Twenty four hours after removal the skin is inspected for a reaction; a positive reaction is determined based on the level of redness and swelling.  (1) Some practitioners find that APT is a great tool to use along side IgE testing in order to a get a more complete picture of all the foods that may be causing symptoms for you or your little one.

Have you tried any of these tests?  We would love to hear about your experience! 



1. Carney, Liesje Nieman. (2009, July). Pediatric Food Allergies. Today’s Dietitian, 11, 48.

2. Joneja, Janice Vickerstaff. (2008, January). Food Allergies: Type II, III, and IV Hypersensitivities. Today’s Dietitian, 10, 10.

3. Keller, Maura. (2010, August). Get Certified- Provide a Valuable Service By Adding Allergy Testing to Your Practice. Today’s Dietitian, 12, 18. 


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Read Comments (4)

  • 2012-04-14 | Dawn

    My son has EoE. With the help of his doctor’s guidance and testing, he has been managed without the use of steroids for two and a half years now.  His doctor uses a combination of skin prick, IgE and APT testing.  He currently tests positive to fifteen food categories, so we use elimination diet to keep him healthy. Great full that our Dr. Uses this combination of testing to help keep our son healthy!!

  • 2012-04-23 | Rob

    It’s great that your son has been able to avoid steroids with the combination of tests that his doctor uses! Since EoE is mostly IgE-mediated, those tests are more helpful than they are with some non-IgE-mediated conditions. Many children with EoE also undergo scoping (endoscopy) and a strit elimination or elemental diet in order to determine what is causing their symptoms. We’re glad Neocate is there to help, when needed!

  • 2012-06-01 | Melanie

    My youngest son has undergone APT twice and it has been very helpful in confirming foods to avoid. The first time we accurately predicted the APT results based on our at home food trials. My son has delayed reactions and always tests negative with traditional blood and skin prick testing. He follows a limited diet of “safe” foods.  Doctors are unsure of his condition, as his symptoms are similar to FPIES and EoE, but are not “classic.”

  • 2012-06-04 | Christine Graham-Garo

    Dear Melanie,
    Usually APT are best used for delayed food reactions. Happy to see you were able to verify the foods with both the food trial and APT. Best wishes for your whole family. Thank so much for sharing your experience!

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Food Allergy Living is a resource for parents of children with food allergies, brought to you by Nutricia, the makers of Neocate. For more in-depth information about our purpose & authors, see our About Food Allergy Living page.