You might want to keep a food diary for several weeks before you get allergy tested. In the diary, write down everything you eat and any symptoms that may occur. But remember if you have delayed food allergies symptoms don't show up for up to 72 hours. If you decide to eliminate something for a awhile, such as wheat, jot down any changes that occur. Then take this diary to your appointment. You also can try an elimination diet where you eliminate all the top allergens (gluten, dairy, eggs, nuts, seafood, soy, peanuts, etc.) for two weeks to a month. Just google Elimination Diet. Keep track again for any improvements. After the elimination phase then you start putting things back one at a time. Or you just try the blood testing.