Originally Posted by glenntaj

First, while currently most medical people think of the anti-tranglutaminase (Ttg) blood test as the most specific for celiac, it may not catch celiac in early stages, as it seems to have a correlation with degree of villous atrophy. And, it may not be as valuable for those who have gluten sensitivity and are not showing intestinal symptoms, but show neurologic or myologic ones.

This is in addition to the info that as many as 20% of biopsy-proven celiacs are negative on all blood tests.

The anti-gliadin has some controversy to it in that it may be a more sensitive indicator of a reaction to gluten, but not as specific to intestinal damage as the anti-transglutaminase. There are other cross reactivities that may result in a "positive" anti-gliadin result. But, some researchers, including Dr. Hadjivassiliou, have shown certain gluten-sensitive patients show with only an isolated anti-gliadin result (and in fact, one of my neighbors falls into that category).

There have been other tests used to support a gluten-sensitivity diagnosis from time to time as well--most notably that anti-endomyesial test--but none of these have a perfect track record. In essence, the best test often is a gluten-free trial to see if one simply functions better over time.

Many people have reported continuing levels of antibodies for a while even after going gluten-free--but one must also be careful that one is completely gluten-free, as it's very easy to get accidentally glutened and get spurious results on later tests. (We had one person who discovered she was getting gluten particles from the BIRD FEED she was putting out in her feeders, of all things.)

I'm not sure what you mean about your daughter--how is she "allergic" to gluten? Allergy is usually thought to mean an immediate IgE reaction to the offending substance, but gluten autoimmunity is a longer-term IgA/IgG reaction, specifically the former. The IgA reaction is so important in these tests that people who have congenitally low IgA generally cannot be tested with the anti-transglutaminase--the results are skewed by the lack of IgA. So how was her allergy serologically determined?

One great source for info on all this, by the way, is The Gluten File, which is right at the top of the board here in the Useful Websites area--lots of info on testing and the differing manifestations of gluten sensitivity:

http://neurotalk.psychcentral.com/thread1872.html