Gluten-sensitive enteropathy (celiac disease) is a painful inflammatory disease of the small intestine that interferes with the absorption of many essential nutrients. It is caused by an autoimmune reaction to gluten (wheat, rye and barley). Several antibodies may be produced during the course of the disease (anti-transglutaminase, anti-gliadin, anti-endomysium). Among these, anti-transglutaminase levels are considered the most useful.
There are two subtypes of anti-transglutaminase antibodies: IgA and IgG. This technique measures the IgA subtype, which is considered the most sensitive. The IgA anti-transglutaminase test is positive in the vast majority of individuals who have the disease and it is used to monitor diet efficacy (return to normal in 3 to 12 months).
Every IgA anti-transglutaminase test is accompanied by a total IgA test. Low total IgA levels could interfere with interpretation of the results. If that happens, see the results of the IgG anti-transglutaminase test.To avoid a false negative that would prevent diagnosis of the disease, it is important to consume gluten (equivalent of 4 slices of bread per day) during the 4 to 6 weeks prior to the test. Unclear results should be repeated on a new sample.