--I hope the celiac tests this doctor ordered include not only the anti-transglutaminase one, but also the anti-gliadin IgA and IgG tests.

The anti-transglutaminase test has been set as the more specific test--but it seems to be correlated, in true celiac, with the degree of villous atrophy of the small intestine. As such, it is likely it comes up negative and misses some people who are in the earlier stages of villous damage. The anti-gliadin tests are less specific, but more sensitive--and, in fact, there is some evidence that it may be the only abnormal test in the earliest stages, or in those whose primary gluten sensitivity symptoms are neurologic, not gastrointestinal.

Our gluten sensitiviy/celiac baord has a lot of info on this, especially in the Gluten File (well worth looking through):

http://neurotalk.psychcentral.com/showthread.php?t=1872