Making sense of food allergy tests

A few months back I wrote about a food allergy panel that our doctor ordered to check my son for food allergies. I really should have asked a lot more questions before agreeing to spent nearly $300 for this testing. It’s expensive and poking your sensory kids finger for blood is a horrible experience for all.

In any case we trusted that the doctor had researched the validity of this test. I should have researched it.  Recalling that my son’s results indicated he had elevated IgG results to several foods.We were told he needed to be off these foods for a period of time to help his body’s immune response calm down.

Four months later, with no improvement, I compared notes with another parent that also reported no change in symptoms/behavior when removing foods based on this same test. This parent ran a follow-up test nearly 6 months into the diet. The results made me questions all of it when I looked at the original and the follow-up.

So what is an IgG?  It’s a “memory” antibody and from what I read IgG antibodies signal past exposure to a food antigen, not allergy to it.  What? Wait….past exposure not allergy?

Of course he was exposes to eggs, whey and gluten in the past and regularly prior to any diet. He was actually already gluten free for a good 5 months before this test was done.

The other child’s follow-up testing showed that the elevated antibodies to those original foods went down which is what you’d expect if you weren’t eating them for 6 months. What we did not expect was there are now elevated antibodies to some of the foods the child has been eating to replace the ones he couldn’t have. So now instead of having elevated IgG to milk, he has it to soy because his cow milk was replaced with soy milk.

So we both looked at each and thought…so does it matter what he eats or are these antibodies just going to go up and down depending on what you eat?

That made me think, wait a minute. How valid is this test?

I am having a hard time finding valid scientific research that demonstrates that elevated IgG to foods actually indicates a food intolerance when the child has no food allergy symptoms to begin with.

Sources:

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