Q. 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?
A. There is a tremendous amount of confusion in this area and I’m happy to try to clear it up.
First it’s important to know exactly what test your doctor ran. Tests for celiac disease are blood tests and the typical ones are tTG and endomysial antibody. Both are fairly sensitive for celiac that is severe, but would “never” show up on an individual who had already eliminated gluten from their diet. Even in untreated celiacs those tests are negative 15% of the time, so they are far from perfect. But for someone who is still eating gluten, feeling ill and wants to know if they have celiac disease, those tests are a fine place to start.
However, a negative blood test above definitely does not rule out gluten sensitivity. If you don’t have celiac disease I very much encourage patients to rule out gluten sensitivity. This is the plan I recommend: Get a blood, saliva and/or stool test for the gliadin antibody. IgA is the best test for saliva and IgG is best for blood – here at the clinic we run both.
Note: When ordering the antigliadin antibody test, both IgG and IgA, be sure the lab does not substitute the deamidated antigliadin test. This test is only accurate for celiac disease and its associated villous atrophy – we’re trying to test for gluten sensitivity which is very different. The non-deamidated tests “ask” your immune system if it’s reacting negatively to the protein gliadin, the definition of a gluten sensitive body.
A positive test means that you are gluten sensitive and need to eliminate gluten from your diet. But a negative test is not definitive because these tests are not as sensitive as they need to be and sometimes there are false negatives. Do not despair! The gold standard for gluten sensitivity is simply what you’ve already done. Remove gluten from your diet for 30 days and see how you feel. If your health is improved that is a positive test right there. Compound that with the fact that when you do stumble upon gluten you don’t feel well and you have all the data you need – you ARE gluten sensitive. No doubt about it.
The other point to know is that when you’ve been off gluten for several months your immune system is unlikely to react to gluten as it hasn’t “seen” it for a while. The only test that claims accuracy even with no gluten in the diet is the Enterolab stool test. I only have experience through patient results but it does seem to be quite accurate. You can contact them on-line, it’s non-invasive and you don’t need to reintroduce gluten before testing.
Dr. Vikki has literally written the book on gluten intolerance, The Gluten Effect and is co-founder and co-director of the renowned clinic HeathNow Medical. You can also visit her blog The Gluten Doctors.