Russ, can you link an article supporting your assertion that small amounts of gliadin are detectable in human breast milk? Not doubting you but it would be nice to have the whole text for reference.

See attachment which is excerpted from this article:   

Got it. Thanks Scott. I'll set up an appointment with a GI after the holidays and get all the celiac disease screening done. Thanks to this amazing forum and to all who have answered my question, I now know what my next steps are.

Aah it sucks that there's no definitive way to confirm NCGS or celiac. I've found a GI clinic that is covered by my insurance and I'll contact them after the holidays to setup an appointment. I hope to get some sort of clarity with further tests. 

Thanks @knitty kitty. I didn't know about thiamine deficiency before you had mentioned it. I'm doing more research into what it is and how I can test for that deficiency. Is Vitamin B1 test the best way to find it? I saw that there is another test: Erythrocyte transketolase activity coefficient (ETKAC) assay to test for thiamine deficiency but I'm not sure how that test is done. Is that something I can take on my own or do I need GI referral. If it does turn out that I'm thiamine deficient, does that confirm that I have celiac disease or could it just mean that I have not been consuming Vitamin B1 rich food and once I address that with a supplement or food, I would no longer be thiamine deficient? Also full disclosure, I'm a vegetarian and only last year I found out that my Vitamin D level was very low. It was 3.7 ng/ml and the ideal range is >29.9 ng/ml. After a year of taking multivitamin supplement, my Vitamin D level has gone up to 27 ng/ml. Though it's better than 3.7 ng/ml, it's still below the range. I'm not sure for how long my Vitamin D level was around 3.7 ng/ml before 2023 as I didn't have my Vitamin D test taken prior to that. My doctor also wanted to check my Vitamin B12 level as I might not be getting enough of it from vegetarian sources. When I took that test last year, Vitamin B12 was 247 pg/ml and ideal range is 200-1100 pg/ml. So it's still within the range though it's on the lower end of the ideal range. I also have recently started taking vitamin b-complex tablets daily. I've never checked other Vitamin B levels including Vitamin B1. Do you know if such a very low level of Vitamin D and moderately lower level of Vitamin B12 would cause celiac disease or may contribute to some of the symptoms I've been experiencing? Regarding the DNA test to test celiac genes, are you referring to HLA DQ2 and HLA DQ8 tests? As soon as I got the result where my IgG was above range, I had ordered the "HLA Typing for Celiac Disease" test in Quest Diagnostics which measures HLA DQ2 and HLA DQ8. The test is 2 weeks from now and I'll post my results here once I receive them.