Specific immunoglobulin E for aeroallergens: 0.35 kUA/L cutoff value is too low

Area of Science:

• Pediatric Allergy and Immunology
• Diagnostic Accuracy in Allergy Testing
• Immunological Biomarkers

Background:

• Specific immunoglobulin E (sIgE) and skin-prick tests (SPT) are common methods for diagnosing allergic sensitization.
• Limited evidence exists on the concordance between sIgE and SPT for aeroallergens in children, risking misclassification.
• A uniform sIgE cutoff of 0.35 kUA/L is widely applied across all allergens, irrespective of specific allergen characteristics.

Purpose of the Study:

• To evaluate the agreement between a 0.35 kUA/L sIgE cutoff and a 3 mm SPT result for ten common aeroallergens in children.
• To determine the optimal sIgE cutoff levels that best correlate with positive SPT results for individual aeroallergens in school-aged children.

Main Methods:

• sIgE levels and SPTs were measured for 10 aeroallergens in 300 children (ages 6-14), including 132 with asthma and 168 controls.
• Cohen κ coefficient was used to assess agreement between sIgE and SPT results across various sIgE cutoff values.
• Data analysis focused on eight aeroallergens due to low sensitization rates for Alternaria and Cladosporium.

Main Results:

• A moderate to substantial agreement was observed between the 0.35 kUA/L sIgE cutoff and the 3 mm SPT cutoff for eight aeroallergens.
• Optimal sIgE cutoffs predicting a positive SPT (≥3 mm) varied significantly by allergen, ranging from 0.75 kUA/L (grass, horse, dog, cat) to 10.0 kUA/L (D. farinae).
• Utilizing an sIgE cutoff of 0.75 kUA/L demonstrated a slight improvement in agreement across all eight analyzed allergens.

Conclusions:

• The standard sIgE cutoff of 0.35 kUA/L appears suboptimal when compared to a 3 mm SPT result for diagnosing aeroallergen sensitization in children.
• Optimal sIgE cutoff values are allergen-specific, indicating that a one-size-fits-all approach is inadequate for accurate allergy diagnosis.
• These findings suggest a need to re-evaluate current sIgE cutoff recommendations and consider allergen-specific thresholds for improved clinical management.