The role of basophil activation test in the diagnosis of pediatric egg allergy in Turkey: A comparison of clinical and laboratory findings with Real-Life Data

Background: Egg allergy is among the most common food allergies in children, significantly affecting the dietary habits and quality of life of both the affected children and their families. This study aims to assess the clinical role of the Basophil Activation Test (BAT) in children with egg allergy and to evaluate its diagnostic accuracy in comparison to other tests. Methods: The study included 46 children with egg allergy. Patients were classified into three groups: IgE-mediated, non-IgE-mediated, and mixed-type allergies. Each patient underwent a Skin Prick Test, serum-specific IgE test, BAT, and Oral Food Challenge. The sensitivity and specificity of each diagnostic test were evaluated. Results: Egg SpIgE positivity was observed in all patients with IgE-mediated allergy (100%) and in 77.78% of those with mixed-type allergy, while only 47.1% of patients with non-IgE-mediated allergy were positive (p = 0.008). BAT positivity was significantly higher in IgE-mediated (72.7%) and mixed-type allergies (50.0%) compared to non-IgE-mediated allergies (17.6%) (p = 0.013). Compared to the oral provocation test, Egg SpIgE had a sensitivity of 0.73 and specificity of 0.33, BAT had a sensitivity of 0.46 and specificity of 0.67, and SPT had a sensitivity of 0.44 and specificity of 0.60. Although Egg SpIgE demonstrated the highest sensitivity, its low specificity makes it less reliable for accurately identifying non-allergic individuals. In contrast, BAT, with its highest specificity and moderate sensitivity, aligns more closely with the oral provocation test in accurately diagnosing egg allergy. Conclusion: When comparing the positivity rates of Egg SpIgE, BAT, and SPT according to allergy types, IgE-mediated allergies showed significantly higher positivity rates. BAT demonstrated high specificity and moderate sensitivity in both IgE-mediated and mixed-type allergies, making it the most compatible test with the oral provocation test for the accurate diagnosis of egg allergy. Given that this test is currently used only for research purposes in our country, it is recommended that BAT be more widely adopted in clinical practice in accordance with guideline recommendations.