--is the most specific (though the least sensitive) for frank celiac (the anti-gliadin tests, which I don't see here, are more sensitive but somewhat less specific and may be associated more highly with non-celiac gluten sensitivity).

The IgA anti-glutaminase test is also the one most closely correlated with villous damage of the small intestine--it is likely that if there was an endoscopy, there would be evidence of flattened villi.

In any case, she needs a gluten free diet. This will mean high vigilance, as gluten sneaks into many things as a filler or binder; it's doesn't just mean giving up bread products. And all first degree relatives should be tested for celiac as well.