What should tTG IgA be if Gluten Free?

[JD-New to Celiac]

I have celiac and I have been gluten free for several years. Very careful and as far as I know I have never consumed gluten. Recently my bowel movements changed dramatically and I have been Bristol 6 for two months and just now moving to Bristol 5. My GI ran all sorts of blood tests and all were good. The celiac panel test for tTG IgA came back at 13.6 (normal <15). My GI said that is normal. Is that normal for someone on a gluten free diet? I am wondering if I did Ingest gluten and the Bristol 6 stools, the abdominal pain, and nausea are all a result of eating gluten. The GI does not think so since I was at 13.6...or in his words "normal". He wants to do endoscopy, biopsy, colonoscopy, because he is concerned it may be something more serious. Could this just be a case of gluten "poisoning"? I feel like my bowel movements are slowly normalizing but still having some issues.

[Scott Adams]

If you’ve been strictly gluten-free for several years, your tTG IgA level of 13.6 (within the normal range of <15) is generally a good sign, as it suggests no significant gluten exposure or ongoing immune response. However, some celiac patients on a gluten-free diet may still have low but detectable tTG IgA levels due to minor cross-contamination, slow healing, or other factors. Your recent symptoms (Bristol 6 stools, abdominal pain, nausea) could indicate accidental gluten ingestion, but they might also stem from other issues like IBS, food intolerances, or gut dysbiosis. Since your GI is concerned about more serious conditions, an endoscopy with biopsy could help confirm whether there’s persistent intestinal damage or another underlying problem. While gluten exposure is possible, the slow normalization of your stools suggests it may have been a transient issue. Continuing to monitor your diet and symptoms while following up with your doctor is wise. If no other cause is found, a trial of an even stricter gluten-free diet (e.g., avoiding processed foods or dining out) might help.

You may want to also try eliminating oats and milk/casein if you can't get the levels lower. 

For people with celiac disease hidden gluten in their diets is the main cause of elevated Tissue Transglutaminase IgA Antibodies (tTG-IgA), but there are other conditions, including cow's milk/casein intolerance, that can also cause this, and here is an article about the other possible causes:

 

 

[RMJ]

The way these tests are developed is they take a bunch of blood samples from people with active celiac disease, and a bunch of samples from people without celiac disease, and run them.  Then they decide where to put the cutoff line for positive such that most samples are on the correct side of the line.  So could it really be a low positive? Yes, although somewhat unlikely.

I’d look at the bigger picture. How does it compare with previous tests run by the same lab? A little difference is normal - run the same sample three times and there would probably be three very slightly different results.  But if it has gone up a lot you may be getting gluten somewhere.