I will tell you this~ I learned I had celiac a few years ago and had my two children tested. The first pediatric GI tested them both for tTG only. My daughter was very high (80 I think), I was crushed when I got the phone call. They said they would be doing an endoscopy, to "confirm". I hated every moment of the process because she had never had ANY surgery or anesthesia, and I had awful anxiety over the whole thing. I will say, it was not bad. Brief, no problems, SHE did great, I just didn't! she ate an omelet that night and woke up normally for school next morning. HOWEVER, her biopsy did not show celiac. I was frustrated when the GI called and said "she may have latent celiac, but we will retest in 6-12 months and she should keep eating normal diet". I hung up the phone and said to my husband, we are going to see someone else.
New GI did more tests, she was positive for endomysial antibody, low in vitamin D, and we discussed her joint pain and occasional reflux, in addition to me having celiac disease myself. He met with me after the results and said "I don't believe in latent, just because the biopsy did not show damage doesn't mean it isn't there~ He drew me a picture, which showed the intestines and how large it really is. If there isn't damage in one spot, there could be one inch lower or two inches to the left. He had no doubt that she had internal damage, because he said when you are positive for endomysial antibody, your intestines are absolutely damaged. We were 100% gluten free after that. All symptoms disappeared (things we didn't know were "symptoms"), at 6 month follow up all labs were normal, vitamin D had more than doubled, and endomysial antibody NEGATIVE. The GI was very pleased and said "that's how it's supposed to work". Take out the offending gluten and body works again.
Times are changing. Many docs are now taking positive labs as a diagnosis.