Question:

I am still researching food allergy tests and most of the stuff I read on the internet is quite dubious as to their reliability. For example here is one comment: “……I agree with what others say – real allergy tests (like antibody test – IgA) show only food you’re seriously allergic to and it probably wouldn’t be your case unless you’re celiac, but the IgG tests are very unreliable – if you have leaky gut, it will show intolerances to almost everything (I had about 25 intolerances out of 100 I tested for). I have done elimination diet with most of them and reintroduced those foods without any problems. But the IgG test didn’t show I didn’t tolerate gluten even though I know I don’t from real symptoms. In other words – tests are useless waste of money (IgG is never covered by any insurance), elimination and reintroduction is the best.” Do you have any thoughts on this?

Answer:

I understand that clients willing to learn more about food intolerance and food allergy become frustrated when searching the internet. Anybody can write anything, right or wrong. And there is a lot of rubbish, mostly from non-informed users or sometimes from non-serious providers of such tests. An interested person can hardly identify what is serious and what is not. Compared to serious journalism, articles on the internet are not really or always trustful. The citation you stated is a good example. It is related to celiac disease, a rare but important intolerance to gluten, which ends up in an autoimmune disease. The author mixes up celiac disease and gluten intolerance which can manifest itself in numerous diseases, mostly extra-intestinal. Food allergy or intolerance tests are not intended to diagnose celiac disease. Positive IgG might give a first indication for celiac disease, but needs to be confirmed by IgA/IgG tests to transglutaminase (what is also recommended in the ImuPro report). A good food IgG allergy/intolerance test is positive to gluten when celiac disease is present and gluten has not been avoided for more than six months. ImuPro is such a test. I suppose the author knew he was celiac and avoided gluten. So evidently IgG disappears and falls below the cut-off value.

Unfortunately the majority of the food allergy tests on the market is not sensitive enough for gluten and may be negative even in presence of celiac disease, particularly if the subject has already avoided gluten.

What is also disturbing for users is that there is no official standardization for IgG food intolerance tests which leads to contradictory results when comparing different tests. Therefore is extremely important to only use tests which have proven their reliability in double-blind controlled studies. ImuPro is such a test.

(Answer is by Dr. Camille Lieners, Scientific Advisor ImuPro)