Correct. However, there is also an IgG version of the anti-tTG that can be used in the case of IgA deficiency. It is possible someone could also have IgG deficiency, but not as common.

Can you humour me and please tick the boxes for me here if you will. If a CD person is IgA deficient they:
Definition makes a difference.

From what I can gather, you may be considered IgA deficient if you have low IgA (below range), but you have Total IgA Deficiency if you are under 7. (I've also read 10). If you have Total IgA deficiency, the anti-tTG IgA test would be worthless. If you have Total IgA Deficiency you also have to worry about things like transfusions.

If you are low IgA, but don't have total IgA deficiency, it is a bit murkier about whether IgA antibody tests are accurate or not. It seems different doctors put different meaning to having low IgA. I've heard some say it would not affect the anti-tTG antibody tests, and I've heard others say it could.

Yes, there is an IgG version of anti-tTG test that can be run in someone who is IgA deficient.

If someone with celiac disease has Total IgA deficiency, yes, the anti-tTG IgA test would be negative. It is important to note that even without IgA deficiency, celiac disease can be seronegative.

The anti-endomysial test also has both an IgA and IgG version. In a perfect world, the anti-endomysial and anti-tTG should give the same result... but it is not always the case. That is why some doctors order BOTH tests. Reducing the screening to a single anti-tTG test, IMO, is a cost saving measure that probably lets up to 20% of those with celiac disease slip under the tracks. While it might be ok for mass screening of the entire population, I think anyone who believes they might have GS/CD deserves to have ALL the tests run. There is the anti-reticulin test as well, that has fallen out of favor even before the antigliadin antibody fell. The anti-endomysial was pushed aside when the anti-tTG came along. I have known one person with celiac disease whose only positive antibody was anti-reticulin.

Still, the anti-tTG can be a starting point, because if it is positive.... you're done! But, a negative result is just the beginning of more testing. And, there are definitely people with gluten sensitivity who get negative results on all blood tests, but improve greatly on a gluten free diet.

The stool test created by Dr. Fine of Enterolab cannot diagnose CD. The stool test looks for gluten sensitivity, and Dr. Fine believes in treating all gluten sensitive people whether they have celiac disease or not. Gluten sensitivity may show in an endless number of ways (as celiac disease does)... including autoimmune disease, depression, GI or neurological symptoms, skin symptoms, and a whole lot more.

"Early Diagnosis Of Gluten Sensitivity: Before the Villi Are Gone" by Kenneth Fine, MD

Diagnosis of Gluten Sensitivity in the 21st Century by Kenneth Fine, M. D.


According to the current mainstream medical standard, only a positive intestinal biopsy can diagnose celiac disease. However, when the anti-tTG is positive, it is about 95% predictive they will find villous atrophy on biopsy. To further complicate, though, there can be false positives blood results.

There is nothing straightforward in this testing. They can make it look simple with a single test but in reality there are many, many ways the testing can be misleading~ with confusing situations arising when blood results don't match biopsy results, etc!


Yes. In this population, it is quite possible that a positive antigliadin IgA or IgG antibody test would be the only positive antibody you may find. Often times only the Antigliadin IgG is positive, considered the weakest of the markers for celiac disease.

In celiac disease, there may be GI symptoms, neurological symptoms, neither or both. It is well documented that celiac disease can be clinically silent (no symptoms!) . It is also well documented that celiac disease can be seronegative (no positive antibodies!).

In gluten sensitivity, there may be GI symptoms, neurological symptoms, neither or both. It follows that someone may show gluten sensitivity by stool or blood test, yet be asymptomatic. It also follows that someone may have gluten sensitivity causing symptoms without it showing on blood testing.

The newly found HLA DQ1 genetic marker is only rarely found in celiac disease. I've read 1-2% percent. I have met a couple positive anti-tTg, biposy proven celiacs via the Internet who were double DQ1, so it always makes me a little crazy when they rule out celiac disease in those without HLA DQ2 or HLA DQ8... but you don't standardize tests based on the 1% exceptions, I guess.

What Dr. H. found through genetic testing of his antigliadin positive neurological patients is that 20% carried the HLA DQ1 type. I would love to see more research in this area because my family happens to have that type... we gluten sensitivity, autoimmunity, neurological and GI symptoms... NO celiac disease. The remaining 80% have JLA DQ2 or DQ8 as seen in celiac disease. I think one of Dr. H's studies or papers says about 30% of his gluten sensitive neurological patients show villous atrophy (have celiac disease as well). Don't quote me on that without finding the paper...my memory sometimes fails me.

I do think the blood testing (including antigliadin IgA and IgG) is worth doing in the event one gets a positive result. I'm open to the stool testing because I know many happy campers who had a positive stool test result and improved remarkably on the diet. In the end, though, one's response to the diet may be the best test of all. The problem when it comes to neurological disease is that it can take a long time (1 or 2 years) to see results IF there are going to be any. I can understand why someone would want a positive test result of some sort to commit to dietary changes for length of time.

I hope this adds clarification rather than confusion. I don't mind trying to explain. There is always a next level of explanation, another pitfall, etc, so keep asking if you are left wondering about anything.

Cara