New Research Argues There IS a Test for Gluten SensitivityMainstream literature continues to state there is no blood test for gluten sensitivity. While it may not be perfect (but what tests are?) some researchers offer a differing opinion, and I wanted to share their results with you.
While there is no further argument of the existence of gluten sensitivity, having a blood test that everyone can agree on has not yet occurred. In a 2012 study published in Clinical Reviews in Allergy & Immunology entitled “Serological Tests in Gluten Sensitivity”, the authors set out to characterize a potential pattern in blood testing that would be helpful in diagnosing gluten sensitivity as compared with celiac disease. They took 78 patients with gluten sensitivity and 80 patients with celiac disease, and retrospectively tested their blood for four standard tests, three of which are classically used for celiac disease, and one that is more commonly thought to be accurate for gluten sensitivity.
For those of you who like the specifics, the tests used were:
1) IgG DGP-AGA (deamidated gliadin peptide antibodies)
2) IgA tTGA (tissue transglutaminase antibodies)
3) IgA EmA (endomysial antibodies)
4) IgG/IgA AGA (anti-gliadin antibodies)And the Winner Is...
Here are the findings: The IgG AGA test was the winner in detecting gluten sensitive patients—56.4% were positive. The test doesn’t rule out the presence of celiac disease however. 81.2% of celiac patients were also positive. The IgA version of the same AGA test yielded vastly different, although not unexpected, results. The test was elevated in only 7% of gluten sensitive patients while 75% of those with celiac disease were positive. Why is that not a surprise?
IgA is found on the mucous membranes of the body where it is exposed to outside foreign substances: nose, lungs, GI tract, ears, eyes, etc.
Since celiac disease mostly affects the lining of the GI tract, it isn’t unexpected that the IgA part of the immune system might be most affected. But when you compared the "classic" celiac tests against the gluten sensitive patients, the results were rather definitive—only one gluten sensitive patient was positive for DGP-AGA and zero gluten sensitive patients demonstrated a positivity for tTGA or EmA. But the celiacs showed a positivity rate of 88.7%, 98.7% and 95% respectively for these three tests.
What Do We Know From This?
A couple of things: 1) Ensure that when you are tested you receive a complete panel of tests, including all those mentioned above. Additionally both the IgA and IgG versions should be included, especially for the AGA test. 2) When interpreting the tests, remember that you are doing more than just ruling out celiac disease.
For many doctors that is their goal. Despite international research knowledge to the contrary, many doctors still don’t appreciate the existence of gluten sensitivity. While no single test is perfect, if you’re suspecting celiac and you test positive for the classic celiac panel of tTGA, EmA and DGP-AGA, then you’ve likely identified your condition. If you know that you do poorly with gluten and test positive for AGA, especially the IgG version, and negative for the rest of the celiac panel, you can feel more assured of a gluten sensitive diagnosis.
Some other tell-tale signs of gluten sensitivity, according to the researchers, are a varied clinical picture, meaning many symptoms occurring at the same time. And while many of these symptoms are similar to another disease, IBS, the authors warn against considering gluten sensitivity as a subtype of IBS. The "extraintestinal" symptoms so common with gluten sensitivity are not typically seen in those patients suffering with IBS, making the distinction clear, in these researchers’ opinion.
The common complaints associated with gluten sensitivity include:
• abdominal pain, bloating, diarrhea, constipation
• foggy mind, tiredness
• eczema/skin rash
• joint/muscle pain
• numbness of legs/arms
• together with a normal or mildly abnormal lining of the small intestine
New Information on Celiac Genes
In the past, the rule of thumb was that "you could never have celiac disease if you didn’t carry the genes for it". That remains true, but these researchers cited findings from 2010 that demonstrated a full 40-50% of gluten sensitive patients possess the same genetic profile as those with celiac disease—HLA DQ2 or DQ8. And with that we watch another stable datum ‘bite the dust’. This opens the door to a new interpretation of genetic testing that doctors should be aware of. Instead of being too quick to tell a patient that while they may have the genes for celiac disease, considering that their blood tests are negative for the disease they’re fine to eat gluten; we now understand that such genes can be present in a case of gluten sensitivity as well. And as we now know, the classic celiac blood tests would be negative in such a case.
I believe we’ll be seeing a wide array of genes responsible for these diseases in the future. But knowing that almost half of those with gluten sensitivity demonstrate the exact same genetic profile as someone with celiac disease is important to know when a patient or their doctor is trying to make an accurate diagnosis. Based on this common gene profile, it is then not surprising to learn that gluten sensitivity can be found in celiac disease family members. In this study almost 13% of the gluten sensitive patients were first degree relatives of celiac patients.
What Might the Future Hold?
As a clinical nutritionist, I have been speaking of celiac disease and claiming the existence of gluten sensitivity for over two decades now. We continue to discover more and more about these conditions. One day there will be a near perfect test and one day we will readily and easily diagnose most all of those suffering. And that my friends, will be a good day! I hope you found this informative.
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To your good health,
Dr. Vikki Petersen, DC, CCN
IFM Certified Practitioner
Founder of HealthNOW Medical Center
Co-author of “The Gluten Effect”
Author of the eBook: “Gluten Intolerance – What You Don’t Know May Be Killing You!”