anti-tTG is the main celiac test used for screening these days, and when positive, it is a very good predictor that they'd find villous atrophy on biopsy. The test isn't perfect, though, and there are sometimes false negative results (some studies say as many as 20% of biopsy proven celiacs are seronegative). So, a negative result does not completely rule out celiac disease, defined by villous atrophy found on intestinal biopsy.

The reason they run total IgA is to make sure someone isn't IgA deficient (far below range, with <7 result), in which case they don't make enough IgA in general to get an accurate result on the test. She clearly isn't IgA deficient. Can't say I've ever seen an above range result before! I have no idea if that has any special meaning, or not.

You can definitely be gluten sensitive without having celiac disease. Many who are gluten sensitive do have other sensitivies, especially casein.

It is not a bad idea to consult with a GI, just to make sure there is nothing else wrong. Most GI's only concern themselves with biopsy proven celiac disease, and down play gluten sensitivity. This is changing though, with some of the big celiac experts now acknowledging you can have gluten sensitivity without having celiac disease. You could request the antigliadin IgA and IgG test, but one needs to be eating gluten for blood test and biopsy to be accurate. Do not start a gluten free diet if you want to pursue this further with a biopsy. If she had a positive result on the antigliadin antibodies, you might find a GI who would proceed to biopsy.

Here is a further explanation of the celiac tests...
http://jccglutenfree.googlepages.com/diagnostictesting
http://jccglutenfree.googlepages.com...ndstooltesting

Gluten sensitivity can affect mood (brain fog, depression, anxiety), and digestive health, so it is definitely worth trying a gluten free diet. But, it may be only part of the answer. Often times nutritional deficiency goes along with food sensitivity, so she may want to begin a well rounded vitamin regimen, for at least six months, to see if she feels any benefits from that. Perhaps a multivitamin, and a good B-complex like Country Life Coenymated B-complex, or Jarrow B-right. These both contain the active forms of B6 (P5P) and B12 (methylcobalamin) which can be important. Most people benefit from fish oil. Low zinc is associated with intestinal permeability. Most people are low in magnesium and vitamin D. It is generally suggested to add new supplements one at a time.

If you had other testing done that shows gluten/casein/ soy/corn sensitivity (what testing was that?) ... I'd just run with it.. and make the dietary changes.... if she is willing. This is a big commitment, and has to be as close to 100% as possible to be effective, so she has to be firmly behind the effort. Gluten, casein, corn and soy do seem to be the top food offenders, and this usually does suggest some underlying "leaky gut" situation. Removing the indicated foods, adding probiotics, adding fish oil and zinc, can all work toward healing the gut lining. B vitamins are important for mood and neurological health.

This is going to be a process as there is rarely any single magic answer, but often times food sensitivity and nutritional deficiency play a big role, and go undetected by our doctors. The thyroid issues can certainly cause big problems all on their own, and so many symptoms tend to overlap many conditions.

You may also want to read up on pyroluria to see if you think it might "fit". I mention it mostly because you say her problems became worse duing stressful times, and pyroluria is a stress related condition, that especially spirals out of control during stressful times. It is also associated with gluten/casein sensitivity, and deficiencies of B6 and zinc. However, I'm not completely clear on what all of her symptoms actually are. Most conditions worsen under stress, as well, but I thought this worth mentioning.
http://jccglutenfree.googlepages.com/pyroluria