Newer Blood Tests for Food Allergies

This heart-lifting story from the Boston Globe tells about an 11-year-old getting the news that her blood test showed that she's not allergic to nuts, peanuts, other legumes and some fruits like she thought she was. Nope, she's really allergic to birch pollen and that rarely causes an anaphylactic reaction. So, on the way home from the doctor's office, she had her mom stop at the store to buy peanut butter, which she describes as "amazing".

While I'm having trouble finding anything about this "new experimental blood test" cited in the article (anyone know anything about it?), I've long been aware of pollen allergies causing food allergy-type symptoms. Personally, I find I get an itchy mouth when I eat certain foods such as raisins and apples during September- or ragweed season as I refer to this month. We've seen similar things with my food allergic child.

One of my go-to allergy books, Allergy Cooking With Ease, by Nicolette M. Dumke lists food family tables. It was in her book that I discovered that almond is really in the plum family. My nut allergic child eats almonds without any problems. Here's an in-depth article, "Molecular Properties of Plant Food Allergens: A Current Classification into Protein Families" that further outlines the classification of plant-derived food allergens. If blood tests are able to distinguish what is a true food allergy from allergies to pollens or plants, we may be able to cross some foods-to-avoid off the list.

Has anyone had experience with these new blood tests? Are you able to eat certain foods in a family but not others- like avoiding peanuts, but can eat peas (both in leguminosae family) or avoiding tree nuts, but can eat almonds?

I just think this is another piece of the food allergy puzzle...


Anonymous said...

No idea about the test but my son can have almonds although he is nut allergic.

Aggie said...

I believe you might be talking about molecular component testing. It is VERY expensive, at about $300 and not yet covered by insurance. What it does is breaks down a peanut into it's most basic form and tests you against each protein in the nut, supposedly to tell you how allergic you might be and if you do have an allergy. I talked to an allergist about these tests and he said they are pretty much only good for people who have tested positive to peanuts, but have never had an ingestion and won't consider doing a food challenge. This test will probably indicate if a there was a false positive on your original(skin or rast) test, but even the component testing has false negatives. I was exited when I first heard about it, but once talking to a few doctors, realized it's not of any use to us.