Good afternoon, I have been living in Norway for 8 months. I still do not have a “fastlege”, my medical service is through the Legevakt. I present many symptoms compatible with celiac disease: migraines, anemia, constipation and diarrhea, flatulence, bloating, Hashimoto's hypothyroidism, weight loss... I have had periods without gluten intake with improvement of some symptoms, especially abdominal swelling. For 3 months I have withdrawn the intake of gluten, but I have not taken into account cross contamination. Until now I did not know that the intake should not be withdrawn without first ruling out celiac disease. My question is, can I ask my doctor for a genetic test before reintroducing gluten? If I am not celiac, I suspect that I have non-celiac gluten sensitivity, and in any case, gluten affects my autoimmune hypothyroidism, so I would not like to start reintroducing it if I do not have a genetic predisposition that forces me to discard the diagnosis of celiac disease. Tusen takk :)
The reason for not remove gluten from the diet prior to getting the diagnosis, is that it may be difficult to diagnose your celiac disease if you do not eat (enough) gluten as celiac disease can only be detected when it is active and you have increased levels of IgA auto-antibodies to the autoantigen Transglutaminase-2 (TG2 is an enzyme) and intestinal changes (small intestinal villous atrophy). These changes disappear on a gluten free diet (although that may take some time).
First, the genetic test is only helpful to minimize your risk for having celiac disease if you do not have the HLA-risk allele, HLA-DQ2.5 or DQ8 that almost everyone with celiac disease have. However, since you have Hashimoto, then you most presumably carry HLA-DQ2.5 as this HLA allele is also a risk allele for Hashimoto. However, it is very common to have it (30-40% carry it). Thus, having this allele does not increase your risk for celiac disease that much.
If you want to be diagnosed, then you need to reintroduce gluten in the diet. You should eat normal gluten containing food (minimum 2 slices of bread/day) in at least 6 weeks before being retested for increased serum levels of IgA anti-TG2, which is the common serum test used to diagnose celiac disease.
Non-celiac gluten sensitivity has been ruled out as a cause of wheat hypersensitivity as it is not the gluten that causes the reaction (blind testing), it something else, presumably a combination of non-absorbable carbohydrates (FODMAP-carbohydrates as Fructans in wheat, which then induce an Irritable bowel syndrome (IBS) like reaction) and other proteins in wheat that may drive an unwanted immune reaction (as Amylase-Trypsin Inhibitor (ATI)).