A Cautionary Tale About Food Allergy Tests

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When a medical professional expresses an opinion that has common sense and is backed by research, it is worth considering.

Dr. Roy Benaroch, a pediatrician, states plainly that if a child can eat a food without experiencing a reaction, then the child is not allergic to it and no testing should be done to see whether that food is a potential allergen.

Having an allergy panel run on children who have not experienced allergic reactions to food is often misleading. A couple recent studies illustrate this.

97.8 Percent Inaccurate

The first study, published in the Journal of Pediatrics, is a review of 800 patients who were referred to an allergy clinic for testing. Nearly 90 percent of the children who had been told to quit eating foods based on these tests were actually able to eat those foods safely.

The study determined that the chance of a positive test predicting a bona-fide allergy was 2.2 percent – meaning a positive allergy test is correct about 2 percent of the time.

Odds Are, No Allergy

The second study involves the recent research suggesting that early peanut exposure helps prevent peanut allergies. Buried within the most newsworthy of this study’s statistics were some other numbers of interest.

For instance, all the babies in this research were given skin prick tests for peanut allergy, and most of those who tested positive – whether they ate peanuts as part of the study or not – turned out not to be allergic. This means if your child has a positive skin prick test for peanut allergies, odds are they will not develop symptoms of peanut allergy.

Too Many Tests?

Yes, some children who test positive on allergy tests do develop allergies, but to have children avoid foods based only on allergy testing is, according to Benaroch, premature.

There are allergy tests being developed that may create an accurate fingerprint of specific proteins a person is allergic to. Until these tests are available, families may be putting themselves under undo stress by believing a child (or adult) has a food allergy when they do not.

You, or your trusted family physician may disagree with Benaroch, but an informed discussion about any medical procedure will never diminish good healthcare.

"Any food allergy testing that is done should only look at foods that seem to have caused reactions in the past, and even then any positive testing should be confirmed by what’s called an 'open challenge,'" Benaroch says. "Under safe conditions, usually under an allergists’ care, give the child some of the food to eat to see what happens. That’s the only real way to test for allergy."

Sources: KevinMD and JPEDS Photo credit: Leonid Mamchenkov / flickr creative commons

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