Tuesday, June 16, 2009

Skin-Prick Testing vs. Blood Tests

A dear friend and I had lunch together today. Both of us have food allergies and both of us have children with food allergies. We got to talking about particular tests that are done to confirm food allergies. The ol' skin-prick test vs. the blood test. Since I am not a doctor, I was curious if one of the tests is better than the other. With Ella we have only done blood tests because of her extreme pistachio allergy. And I have only had the skin-prick tests. So I did a little research and found these two articles that do an excellent job of breaking down each test... Food Allergy Testing and Tests for Allergies.

From what I have read, the skin-prick test is actually considered more reliable. That surprised me a bit. If there is a reaction on the skin you can be certain that there is an allergy to a given food. The blood test measures specific allergic antibodies in a person's blood. It seems that many people can actually eat something that they test positive to with the blood test. I am wondering if these things are on the low or high reaction scale? And I also wonder if there is no reaction, seemingly, is there an adverse reaction that is harder to track? For instance, if gluten intolerance is not addressed it has been known to cause fertility issues in women. Other things that I have read suggest that the blood test is most helpful in determining the level of allergy, on a numeric scale. Our doctor often breaks down Ella's blood test results in categories like "low, moderate, high, and severe". Soy is in the low category, whereas pistachios are in the severe category. One of the biggest advantages to the skin-prick test is that it is much cheaper to do. Personally, I like knowing what I am up against. Is this beast little or BIG?

Ella and I will be getting hers and hers matching skin-pricks next month. I will be quite curious to see how all of that will stack up against her previous blood tests.

Another friend, who's child has severe food allergies just had some extensive testing done on her 2 year old son. He has horrible issues with asthma and they have seen several specialists who have not helped this poor child's situation. Now they are seeing a doctor who does blood, urine and fecal testing. She matches allergy results with genetic testing. It sounds like a fascinating and thorough process. It took my friend several months to get all the results from the tests. The information that they got back was shocking. He is allergic to a great many things including, wheat, gluten, corn, soy, all nuts, watermelon, cantaloupe, coconut, plus many, many more. Thankfully, he is not allergic to rice which will now be the foundation of his diet. Their doctor is suggesting vitamin supplementation with his new diet. My friend is feeling overwhelmed by all of this, as you can imagine. It is sort of like doing a rigorous obstacle course just to get dinner on the table. All day, every day. And this kid is only 2! I hope that all of this hard work will have a payoff very soon.


ChyvonneB said...

I have been tested for food allergies/intolerances by an allergist/immunologist. I have a history of Graves' Disease, and Autoimmune Disorder along with other health issues.

The skin test only showed allergies to environmental items such as dust mites and ragweed. The blood test showed at least 14 food intolerances. I'm sure there are probably even more foods that I'm sensitive to that don't necessarily show up on a test.

It turns out that I have Leaky Gut Syndrome or Intestinal Permeability as well. This was diagnosed after I sought out an Integrative Doctor. I figure this (LGS) and my other health issues and/or medications helped to cause my food intolerances by damaging my intestinal lining.

So, the allergist told me to remove the 14 items from my diet for at least six months. He went ahead and retested at my request after 3 1/2 months. My levels have gone down to zero. For this test, the highest level was 6. Milk, for example, was a 3 for me.

My allergist said that if I would have kept inching up on the scale for some of my intolerances, they could become life threatening. Surprising! So, I will probably have to eat differently for the rest of my life (i.e. by incorporating aspects of the rotation diet) and do what I can to repair and keep my intestinal track okay.

Allergies are different from intolerances. But, I guess an intolerance can certainly become an allergy. It seems that not many doctors are well versed on this (or leaky gut sydrome, for that matter.)

Good luck and God Bless!

Anonymous said...

I get testing for my daughter once at year, just to see if anything has changed. She's 6 with tree nut (pistachio, cashew most severe) and peanuts.

At first we just did blood testing for all nuts and peanuts always turned up zero. Last summer we did skin prick teting and peanuts registered almost as high as pistachios but still shows up as zero on the blood test. So from now on, we are doing blood and skin testing. I'm always hoping the numbers will go down and be outgrown :)

Good luck with the testing


Heidi Miller said...

Thank you so much for your comments! This information really helps!