What is a cross reactivity?
A cross-reactivity happens when the IgG antibodies in your blood sample confuse a food protein in the test for a certain environmental allergen (like pollen, mold, etc.) that you’ve recently been exposed to. This can happen when the proteins in environmental allergens “mimic” the proteins found in certain foods.
If you’ve never eaten the food—or you haven’t eaten it in a year or more—a cross-reactivity could be to blame for an unexpected IgG reactivity you see in your test results. Remember: you have to eat the food for it to stimulate an immune system reaction (or cause symptoms).