Specific IgE Decision Point Cutoffs in Children with IgE-Mediated Wheat Allergy and a Review of the Literature

Background: Wheat IgE-mediated food allergy in children is one of the most frequent food allergies in westernized countries, affecting between 0.4 and 1% of children. Although 95% predictive decision points have been determined for major allergens such as peanut, egg, and milk, the diagnostic performances of wheat-specific IgE (sIgE) and wheat component testing are not well established. Objectives: The aim of this study was to determine sIgE decision point cutoffs in children with IgE-mediated wheat allergy and provide a review of the literature. Method: A retrospective review of wheat oral food challenges was performed at the pediatric allergy unit of the University Hospitals of Geneva between 2004 and 2019. Performance characteristics for wheat and omega-5 gliadin sIgE were calculated and positive and negative OFC data were compared using the Mann-Whitney U test. Results: A wheat sIgE cutoff of 2.88 kU(A)/L had a sensitivity of 95% (negative decision point), whereas a cutoff of 78.1 kU(A)/L had a specificity of 95% (positive decision point). When giving equal weight to sensitivity and specificity, the optimal cutoff point for wheat sIgE was 12 kU(A)/L, which gave a specificity of 70% and a sensitivity of 66.67%. Conclusions: These findings suggest a high positive decision point for wheat sIgE (78.1 kU(A)/L). This reinforces the importance of considering OFC in children with IgE-mediated wheat allergy to confirm diagnosis even in patients with relatively high wheat sIgE values, as there is a risk of falsely mislabeling these patients as allergic.