A Straightforward Algorithm for Diagnosing Hymenoptera Venom Allergy and Identifying the Relevant Venom for Immunotherapy

Background: Routine allergy diagnostic assessment relies on the patient's medical history, skin testing, and the detection of specific IgE (sIgE) in the serum. In addition, molecular allergy diagnostics and the basophil activation test (BAT) can be used; however, these additional tests are costly and sometimes time‐consuming. Therefore, our objective was to identify the test with the highest sensitivity, determine the most effective combination of tests to enhance sensitivity, and develop a simple IgE ratio to distinguish between bee and vespid venom allergy in cases of double positivity.

Methods: We retrospectively analyzed data from 190 bee venom‐allergic and 809 vespid venom‐allergic patients, along with 61 non‐allergic subjects. Sensitivity and specificity were assessed for sIgE (ImmunoCAP), the intradermal test (IDT), and the BAT.

Results: Applying a lower cut‐off of 0.1 kU/L in patients with total IgE < 30 kU/L (while keeping the standard cut‐off of 0.35 kU/L otherwise) increased sensitivity for sIgE to bee venom from 85.7% to 94.6% and for vespid venom from 92.2% to 97.0%. The highest sensitivity (100%) was achieved by combining this sIgE dual cut‐off approach with the intradermal test for bee venom allergy, while sensitivity for vespid venom allergy reached 98.5%. A vespid/bee ratio ≥ 2.68 indicated vespid venom allergy with 59.3% sensitivity, while a bee/vespid ratio ≥ 5.33 identified bee venom allergy with 50.6% sensitivity, both with 100% specificity.

Conclusions: Conventional tests, such as sIgE determination or intradermal testing, are usually sufficient. Combining both increases sensitivity, while additional tests provide no further benefit. Double‐positive findings may often be clarified using a simple sIgE ratio, though sensitivity remains limited.