Levels of specific IgE that predict food allergy reaction

The level of IgE increases during childhood until about 10 years of age. At age 10, the total IgE reaches a value that is typically maintained throughout adult life.

For egg, milk, peanut, and fish allergy, diagnostic levels of IgE, which could predict clinical reactivity in this population with greater than 95% certainty, were identified:

- egg, 6 kilounits of allergen-specific IgE per liter kU
- milk, 32 kU (or 15 in newer studies)
- peanut, 15 kU
- fish, 20 kU

For egg, milk, peanut, and fish allergy, diagnostic levels of IgE, which could predict clinical reactivity in this population with greater than 50% certainty, were identified:

- egg, 2 kilounits of allergen-specific IgE per liter kU
- milk, 2 kU
- peanut, 2 kU

References:
http://www.ncbi.nlm.nih.gov/pubmed/9338535
http://www.ncbi.nlm.nih.gov/pubmed/11344358
http://www.questdiagnostics.com/hcp/topics/immunocap/immunocap.html

Pearls and Pitfalls of Allergen Testing - JCAAI http://goo.gl/6ThcC and http://goo.gl/Bfnhn


Levels of specific IgE that predict food allergy reaction (click to enlarge the image).


8 top allergens account for 90 percent of food allergies. Specific IgE levels (sIgE) that predict the likelihood of passing an oral food challenge are shown in the figure. (click to enlarge the image).



Comparison of diagnostic methods for peanut, egg, and milk allergy - skin prick test (SPT) vs. specific IgE (sIgE) (click to see the spreadsheet). Sensitivity of blood allergy testing is 25-30% lower than that of skin testing, based on comparative studies (CCJM 2011).

Overdiagnosis of Food Allergy: IgE and skin-prick testing should be confined to the realm of experts (allergists). Medscape, 2011.