--for frank celiac would be a gastrointestinal biopsy with evidence of compromised villi in the small intestine. Even this is not always certain, as, depending on where the samples are taken, evidence of this may be missed, especially if the damage in early and patchy.

But, failing that, the blood test results to seem to show at least some reactivity to gluten, so it couldn't hurt to gluten free, and certainly might help.

As I said in the previous post, there are manifestations of gluten sensitivity that occur outside the small intestine that some would not refer to as celiac (dermatitis hepatiformis, gluten ataxia, etc.) that would still indicate a need for a gluten-free diet.