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Testing For Gluten Allergy/Sensitivity – Your Result Can Be A False Negative!

Many of us are already aware of the myriad of health issues that can be related to gluten allergies, sensitivity and intolerances. Don’t worry, this article is not about going over what many of our readers already know (though if you need more information about what gluten is and what symptoms may be associated with its sensitivity, please see our article on gluten intolerance posted last year by clicking here). I would like to explore the variety of tests that are available, explain why so many have false negative results and detail the differences between celiac and gluten sensitivity and which tests are used for each. Even if you think you already know everything there is to know about gluten, please read on and I promise you will learn something new from the below.

Let’s Start By Clarifying Some Definitions

Celiac disease is an extreme intolerance to gluten where eating gluten will actually damage the lining of your intestines and cause mal-absorption along with many other symptoms such as all types of GI issues, skin issues, headaches, arthritis, depression and the list goes on and on.

A gluten sensitivity is when you do not have true blown celiac and your intestines are not completely damaged but eating gluten makes you feel worse and can often cause very similar if not the same symptoms of those with celiac disease.

What Are The Problems With Testing And Why Is It So Hard To Get A True Answer?

Testing for this is very tricky because the occurrence of false negatives is often likely. The only way to get a true celiac test is to go to the GI doctor and have a biopsy. Your intestines are lined with hair like structures called villi and in healthy intestines; they stand straight up like a shaggy rug. When a person has celiac disease, gluten causes damage to the intestines and the villi lose their integrity and become flattened – you can think of this looking more like a berber carpet instead of a fluffy rug. The biopsy looks at the state of the villi and only if they are flattened can there be a true celiac diagnosis.

A very important thing to note here is that if someone removes gluten from their diet, the villi can be revived fairly quickly and thus the intestines will heal. For this reason a person needs to actually eat gluten (equivalent to at least 1 slice of wheat bread) every day for 30 consecutive days before the biopsy in order to get an accurate reading. Patients who already started a gluten free diet prior to their biopsy can often get a false negative because of this.

There is also a way to look at antibodies your body may be producing against gluten in the blood and some GI doctors use this as a celiac test. (An antibody is something that is made when the body is fighting an antigen that it doesn’t like hence a present gluten antibody shows that there is some kind of a reaction). The problem here is that the gluten antibodies are produced in significant numbers only if the person has a good functioning immune system and has a good amount of total antibodies since the gluten antibody is a part of the total. If the total antibody production is low (which is common in many people especially if there is a chronic health condition) the gluten antibody will also be low therefore leading to a false negative result.

Furthermore, there are several types of antibodies that can be tested such and some of the main ones include IgE, IgG and IgA. IgE shows an immediate response and this often comes out negative unless someone has an anaphylactic shock type reaction to the food which is far less common. IgG and IgA are the delayed antibodies and are more likely to be found through testing because gluten containing foods take several hours to several days to show symptoms and inflame the immune system so the delayed antibodies can better catch this reaction. I have seen people who were told by their doctors that they did not have any issues with gluten but upon review of their blood results, the IgE was the only antibody tested which only shows a tiny piece of the picture.

What About Sensitivities?

While celiac disease is becoming more common, gluten sensitivity is much more rampant and affects an even bigger part of the population. Even though a sensitivity is not full blown celiac, the symptoms can be very similar and range from digestion to all other areas of the body. Those with a gluten sensitivity will not get a positive result through a biopsy and can often test negative on the gluten antibody blood test however notice they will feel worse when consuming gluten. This leaves many people confused and drives them to eat gluten even though they feel bad from it because they have been told by doctors their tests are negative and they do not have an issue with gluten.

When a celiac test is negative but someone feels worse after consuming gluten (this can happen from 1-72 hours post consumption) they most likely have a sensitivity to gluten. The reason the other tests are negative is because gluten reactions vary in strength. The easiest way to describe this is if you think of a spectrum from 0 to 100 with 0 being no sensitivity and 100 being extremely sensitive. If someone is all the way at 100 it would equate to celiac disease and/or extreme intolerance and often result in a positive biopsy but anything below that would not show up on those tests. So the problem is what if you are at 95? or 85? These cases would show up negative for celiac but as you can see from the example, 95 is still very high on the spectrum and the person would have a pretty severe sensitivity to gluten with all the same symptoms.

Testing for sensitivities is also tricky because people can react to gluten through various allergenic pathways and being able to find a possible reactive pathway is the way to see a true result. The major pathways that have been identified and where testing is available for food sensitivities so far are the delayed antibody pathways and inflammatory cell mediated pathways.

Antibody testing is very popular and used in many integrative practices all over the country. Antibodies can also be tested in blood, but only the IgA and IgG should be used (not IgE) as those are the delayed ones and of course the total antibody would need to be assessed because if that is low, the IgA and IgG would be considered invalid. IgA and IgG antibodies can also be tested in stool and saliva. There are different opinions on what is best (some say gluten is in contact with stool more than blood or saliva thus stool may be more accurate) but most likely testing in all 3, (blood, saliva and stool) is probably better because if at least one of those is positive, it means there is a sensitivity. If budget or other issues do not allow to test all 3 body fluids, I believe that stool gives a more accurate picture because food sits in the intestines longer than it does in saliva or blood hence there is more of a chance to see a reaction if one does exist.

The Story Doesn’t Stop Here Though

It is possible that all 3 antibodies tested in all 3 body fluids can turn out negative but a reaction can still be occurring. This is possible because the body can react to gluten on a cellular level without necessarily producing antibodies, or as mentioned above, if the total antibody is weakened due to immune weakness and other diseases, the antibody test would not be valid.

Another way to look at gluten sensitivity is through the inflammatory pathway of the white blood cells. The ALCAT technology has made their name in this area and they test by collecting blood, separating out the while blood cells and then introducing gluten to the white blood cells to look for information. If the while blood cell changes form/shape the result is positive and the severity of the change the white blood cell undergoes allows the technicians at the lab determine if the sensitivity is mild, moderate or severe. If there is no change to the white blood cell, there is no sensitivity.

What If Biopsy, Antibody And Inflammatory Tests All Show Up Negative But Symptoms Are Still There?

Another big piece of the gluten puzzle is a gluten intolerance due to the slight genetic change of the seeds of wheat. This phenomenon is outlined wonderfully in Dr. Davis’s book “Wheat Belly” which is a great read. The premise here is that about 50 years ago, a geneticist was able to slightly modify the wheat seed to allow the wheat plant to grow faster and be harvested more often to help with world hunger. While this was a great intention, the genetic modification in the seed created a plant that now has a higher gluten content. Also while plants can naturally mutate from strain to strain over time, the natural process can take hundreds of year and this was done overnight. The human DNA is not familiar with this new strain of wheat and thus there are many people who are just plainly intolerant to this new wheat as their body cannot recognize this changed grain. Dr. Davis uses a wonderful analogy in his book to describe it. The new wheat is 99.9% genetically the same as the old wheat which doesn’t seem like it would be that harmful, but apes are also 99.9% genetically the same as humans and yet we are quite different.

This new intolerance that comes from this genetic change does not necessarily cause your body to be sensitive which is why it is so hard to test for it, but people are finding that they just don’t feel well when they eat wheat and this can be the answer why.

The Final And Perhaps The Most Important Piece Of The Puzzle – Your Genetics

I saved the best for last! One extremely important factor that is often missed when talking about gluten sensitivity/allergy is genetics. Genes are something that you are born with and are carried down from generation to generation. There are a set of genes recognized as celiac genes and they are called HLA DQ2 and DQ8. We now know that the DQ2 gene has 2 pieces each with 2 alleles for a total of 4 and the DQ8 has 1 allele for a grand total of 5 different alleles so we need see all of them. Studies show that if you have a specific number of these genes segments, your body is not designed to process certain gluten proteins and therefore you may have celiac already or will be likely to become gluten intolerant/sensitive.

Gluten sensitivity is not a disease like celiac disease but can be looked at as a state of genetics. If a person is not designed to process gluten properly based on their genetics but eat it anyways, the end result is a constant attack on the immune system which can subsequently lead to autoimmune disease. But if we knew a person’s propensity was to be gluten sensitive, we can stop the disease before it even happens.

Most labs only do 2 of the gene pieces, but since we now know that there are  others pieces that  measure non-celiac gluten genes (Yes! there is actually a type of gluten in corn and rice, but more on that next month) it is essential to have a complete profile of all of them. I have been searching for labs and found a panel that does all the peices. They are a subsidiary of Labcorp so there is a good chance the test may even be covered by insurance which is a huge plus!

What Is The Best Test Then?

Depending on who you ask, you will most likely get different answers, but as you can see from the above discussion there are several ways to look at gluten issues. They are all important and the only way to know for sure is to look at all the pathways through various tests and if any are positive then you have an issue with gluten. Please don’t just take one test and assume things are ok if only that one test is negative, especially if you may not feel well with gluten or have an autoimmune disease.

After a lot of research, I believe that looking at genetics holds the biggest key in the gluten puzzle. All the other tests measure only a fraction of how a person’s immune system can react to gluten but genetics can actually tell us what the immune system is going to do in the future.  

You cannot control what genes you are born with, but you can identify them and change your diet and lifestyle to accommodate them to both heal a health issue as well as prevent a potential future health issue.  There is a lot more that I want to tell you about the genetic gluten connection with autoimmune disease and the different types of glutens found in other grains but I realize this article is already getting very long so stay tuned for next month for the continuation of this discussion.

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