Specific-IgE Classification and Interpretation

Specific IgE levels higher than 0.35 kU/L suggest sensitization, but that is not synonymous with clinical disease.

The likelihood of an IgE-mediated clinical reaction often increases with the level of specific IgE, but these levels do not predict severity or guarantee a reaction will occur.

Blood tests are usually considered positive if the allergen-specific IgE level is greater than 0.35 kU/L; however, sensitization to certain inhalant allergens can occur at levels as low as 0.12 kU/L.

If an individual is sensitized, and shows signs and symptoms on exposure to the antigen, avoidance/elimination is recommended.


Class Specific-IgE kU/L Interpretation
0 <0.35 Undetectable/Negative
1 0.36-0.70 Equivocal/Very Low
2 0.71-3.50 Positive/Moderate
3 3.51-17.50 Positive/High
4 17.51-50.00 Strong Positive/Very High
5 50.01-100.0 Strong Positive/Very High
6 >100.01 Strong Positive/Very High
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