Answers From A Gluten Doctor – Part 6: Testing, Testing, Testing
From the number of emails I received requesting that Dr. Vikki clarify testing for gluten sensitivity, apparently I am not the only one confused.
I recently had a blood test (ordered from another doctor) and he proceeded to tell me I tested negative for gluten intolerance. As we know I have tested positive many times in the past and the simple truth is when I eat gluten I feel like crap and when I don’t, well, I don’t. Did I test negative because I have been gluten free for so long? Any advice to others that have a similar experience?
Let’s begin by reviewing the various tests available for diagnosing gluten sensitivity and celiac disease as well as their accuracy level and any inherent weaknesses.
The following tests are used to rule in Gluten Sensitivity and not to rule it out because there are many false negative test results. If any one of the testing methods below shows a positive reaction to gluten then you need to consider yourself gluten sensitive.
1. Small Intestinal Biopsy –an invasive test showing specific cellular changes associated with celiac disease. If it’s positive it means you have celiac disease and have lost most of the surface area of your small intestine which is very serious. It is not considered a sensitive test because so much damage has to occur before it is positive. It is possible to have celiac disease in an early stage or gluten sensitivity without this test showing positive.
2. IEL (intraepithelial lymphocyte) count –an early marker for celiac as well as gluten sensitivity, but it can only be done invasively, similar to the small intestine biopsy.
3. Serum anti- transglutaminase – a blood test that is the first test typically used to determine the presence of celiac disease. Similar to the intestinal biopsy it only tends to be positive once severe damage to the small intestine has occurred.
4. Deamidated anti-gliadin antibodies – a blood test used to detect celiac disease. This is considered to be one of the more sensitive tests currently.
5. Genetic Testing – a simple buccal swab will let you know if you carry the HLA DQ 2, 8, 1 or 3 gene. (The latter two are felt to be associated with gluten sensitivity vs the first two that are associated with celiac disease.) Having the gene shows a susceptibility but doesn’t guarantee that you will get the disease.
To your good health,
Dr. Vikki Petersen