Posted 7/16/2013 1:59 PM (GMT 0)
If you have a genuine food allergy, then you will have an almost immediate reaction to even a tiny amount of the food in question. The reaction would be unmistakable (itching, swelling, rash, spreading hives, vomiting, diarrhea, breathing difficulties and more.)
Genuine food allergies involve an IgE response and can be identified by skin prick tests or RAST blood tests and confirmed with avoidance and challenge.
There is the possibility of food intolerance (a very different concept to a genuine allergy), which can be delayed up to 48 hours or more, or the effects can be cumulative.
There are there are no laboratory tests to accurately measure food intolerance as it does not involve an immune response. It is a pharmacological reaction to certain chemicals in food.The only way to identify provoking foods is through a comprehensive elimination diet and careful challenges.
(I realize that IgG testing is currently being touted as a way of testing for food intolerance however, since food intolerance does not involve the immune system, these tests give many false positives.)
Good luck, glad you are feeling well.