--that one, I believe, is the anti-transglutaminase assay, which is most specific for determining possible villious atrophy.

A negative test there, though, wouldn't eliminate the possiblility of a gluten problem--that's why most of us say the anti-gliadin tests should also be performed--positive or high range results on those are not as specific but do indicate that the body is reacting (creating antibodies) to gluten proteins.