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 |
