For several years now, doctors have been wondering why allergies seem to be on the rise - now it appears that allergies may not be on the rise so much as inaccurate results of allergy tests. Recent studies have shown that blood tests for allergies are less than 50% accurate, giving a false positive result more than half the time. Having your blood tested for allergies is far simpler than getting a scratch test. Having had both, I can attest to this! With a blood test, they simply withdraw the blood, then whisk it away to a lab, and later you get the results. For a scratch test, one must sit on the doctor's table, on that crinkly tissue paper, for hours at a time while a variety of nurses and nurse's assistants poke you with tiny syringes. It's tedious, and painful, and the itch of a positive result is absolutely awful. (They chide you if you scratch. Ask me how I know.) The failure rate of blood allergy tests is of particular concern with food allergies. Testing positive for an allergy to a food you're not allergic to has a huge impact on quality of life. For children, it can even be life threatening, since their growing bodies need the widest possible assortment of nutrients. Blood tests are inaccurate because they are not able to reliably distinguish between the proteins found in different foods. As the New York Times article points out, "A child who is allergic to peanuts, for instance, might test positive for allergies to soy, green beans, peas and kidney beans. Children with milk allergies may test positive for beef allergy." A scratch test is far more accurate, because it tests for the actual immune response, using the actual (suspected) allergen. In other words, a blood allergy test is like walking into an empty pet store and making a list of the animals the store sells, based on the bedding in the cages. You may see a series of hamster cages, and write down "hamster, gerbil, guinea pig." A scratch test is like walking into a full pet store, and listing the pets that you actually see in the cages. I had an allergy blood test when I was 14, which showed that I was allergic to a wide variety of plant life. This certainly was true to some extent (I went in for severe hay fever). At the age of 34 I had an actual scratch test, which showed that I was NOT allergic to 75% of the things which the blood test had shown a positive. The doctor assumed that, in the intervening years, I had lost some of the allergic response that I had as a teen. Now I have to wonder! If you have tested positive for an allergy, after a blood test, doctors now strongly recommend that you re-test with a scratch test. Considering the inaccuracy of blood tests, it's almost a guarantee that you will turn out to NOT be allergic to something that you originally tested positive for.