Not DF but, food allergy test for dogs are known to be inaccurate, giving both false negatives and false positives. This is because the tests only test for one type of immune response and dogs actually have several different immune responses to allergens, and they can have the one type that is tested for for more than one reason. If you go to the websites of the various companies that put out all these tests, they all post the disclaimer that their tests are not accurate and the standard for diagnosing food allergies is a properly run elimination diet. If the companies that make the tests suggest you do a food trial instead of using their test, I would listen to that bit of advice.
