Test results question

[BamaGal78]

My 13 year old son has been having random episodes of vomiting after eating for the past 6 months or so. His 15 year old sister is a type 1 diabetic and has celiac (for over a decade now), so I know he's at an increased risk. Although we are gluten-free in our home, at restaurants, he isn't restricted from gluten and this is where each of these vomiting episodes has occurred. As he doesn't have issues with diarrhea, constipation, ongoing abdominal pain, or anything, I had just brushed the first couple off as a fluke, especially since it doesn't happen EVERY TIME we eat out. Yesterday, though, he had a lab draw which included ANA, IgA, and Ttg IgA. His ANA is negative and Ttg IgA is  <0.5U/mL (reference range is >15.0U/mL). His serum IgA is low, though, at 36mg/dL (reference range 58-358mg/dL) and sed rate/ESR is also low at 2mm/h (reference range 3-13mm/h).

That being said, he was COVID positive last week and is a chronic moderate asthmatic with moderate allergic rhinitis.

Do you think I should be feel reassured that he does not have celiac? To my understanding, with celiac, his IgA would be elevated as would his Ttg IgA, but instead his serum IgA is low? Can anyone help me puzzle this out? Our doc will be of little help as these were just tacked on there at my request and not because he knows anything about celiac in general.

Thanks in advance!

[trents]

Welcome to the forum, BamaGal78.

It is not uncommon for total IGA to be low in children and for their immune response with regard to celiac disease to be atypical. Their immune systems are still immature. When total IGA is low, it will depress the numbers for individual IGA scores. That underscores the importance of getting a "full celiac panel" performed which includes other possible celiac antibody components such as IGP and DPG instead of just the total IGa and tTG-IGA. There is a dearth of knowledge in the medical community regarding celiac disease, it's full range of symptoms, prevalence in the population and how to properly diagnose it. People who suspect celaic disease must go armed with knowledge and be prepared to respectfully advocate for themselves and their loved ones if proper testing is to get done.

Here is a primer for celiac antibody testing: https://celiac.org/about-celiac-disease/screening-and-diagnosis/screening/

I would go back and insist on more complete screening. I would request all the tests outline in the link above. the tTG-IGA test misses 20% of those with celiac disease who are of white European decent and 80% of those of black African decent. None of the antibody tests are perfect and so it is important to have numerous ones run. Some are more sensitive than others and some are more specific than others.

It is important to make sure your son does not begin a gluten free diet until all testing is complete or the testing will be invalidated.

 

[trents]

It is also possible that your son has NCGS (Non Celiac Gluten Sensitivity) which is 10x more common that celiac disease but for which there is no test. celiac disease must first be ruled out. They share a lot of the same symptoms.

[trents]

After rereading your original post I just want to reinforce what I already said about continuing to consume gluten until all testing is done. Sounds like your son is only getting sporadic exposure to gluten. The Mayo Clinic guidelines for pretest gluten challenges is the daily consumption of two slices of wheat bread (or the gluten equivalent) or 6-8 weeks leading up to antibody testing and for at least two weeks leading up to an endoscopy/biopsy. I'm afraid your son's occasional but not regular exposure to gluten has skewed his tTG-IGA downward.