The proof is in the eating!
Food allergy is a clinical diagnosis. It is not a laboratory or skin testing diagnosis. The proof is in the eating, not the testing. Skin tests and lab tests are based on probabilities, not absolute certainties.
IgE (the allergic antibody) grades and classes (Class 1, Class 2, Class 3, etc.) and terms like low, mild, moderate and severe are arbitrary and may vary from one laboratory to another. Pentucket Medical Allergy does not use such subjective grades or classes.
IgE is measured in Ku/Liter, or “units”.
IgE levels that indicate a 95% chance of an allergic reaction are:
- Egg White 7 units 2 units if under two years old
- Peanut 14 units
- Milk 15 units 5 units if under two years old
- Soy 30 units
- Tree Nuts 15 units
- Fish 20 units
- Wheat 26 units
IgG is not an allergic antibody. Therefore, allergy testing with IgG is meaningless.
95% chance of allergic reactions:
- Egg 7mm or larger
- Peanut 8mm or larger
- Milk 8mm or larger
BE AWARE of Unacceptable Food Allergy Tests!
Testing predicts the likelihood of a reaction, not the severity. Testing can and often is falsely positive. For this reason, patients should not generally be tested for foods that they tolerate or that they have never previously eaten.
One form of food allergy skin testing, called the intradermal test, is not recommended by the American Academy of Allergy because of extremely high false positive rates and risk of reactions to the testing itself. If your allergist suggests intradermal testing for food allergies, you should seek a second opinion.
Food allergy testing cannot help with food intolerances, such as lactose intolerance. Intolerance is an unpleasant reaction to food that is NOT caused by an allergic reaction.
Remember, a patient isn’t diagnosed with a food allergy just because of a positive skin or laboratory test. If a patient is able to eat a food with no symptoms or reactions before testing, they can eat the food after testing.
Get more information, office hours and locations, and meet the Pentucket Medical Allergy team on our website!