DISCUSSION
DBPCFC, allergic, allergies
RECRUITMENT, PEANUT ALLERGY, EGG ALLERGY, ALLERGIES
Most egg allergic children tolerate BE.There are many strengths to underscore in this diagnostic study. First, the BAT2 study was rigorously designed according to the STARD guidelines.Our results for BAT in the diagnosis of egg allergy, like previously for peanut allergy,Importantly, the BAT2 study improved our understanding of the diagnostic performance of the tests we already have available in clinic, such as SPT and sIgE, and of how we can optimise the results provided to improve patients' outcomes. Ongoing validation will confirm whether the diagnostic cut‐offs we defined are generalisable to other centres in the United Kingdom and the world. Some of our findings for SPT and sIgE are consistent with previous studies, for instance, the lack of added value of testing patients to both EW extract and the actual food, either as raw egg or BE.Children were advised to avoid baked egg for 2 days prior to the challenge given due to the possible interference of egg allergens in circulation with the outcome of the OFC and/or the BAT. This was decided based on the findings of the peanut oral immunotherapy study by Thyagarajan et al.Despite the many strengths, we must acknowledge some potential limitations of our study. First, the fact that study participants were referred to the study based on their need for OFC, that some patients were excluded due to concerns over high IgE sensitisation and high likelihood of reaction during the OFC, and that other patients declined participation or ended up not undergoing OFC for a variety of reasons may have created some selection bias. However, these aspects also reflect the relevance of the selected population to the research question and to day‐to‐day clinical practice. Moreover, our study population is based on sequential recruitment which guarantee an acceptable degree of randomness of the sample and is obtained by numerous independent clinicians which guarantee the representativeness of the target population. Second, we cannot exclude that the sample size adopted may have limited our study with some false negative results. However, we showed that lack of statistical power affects our study only for AUC below the value of 0.7, a value that is not of clinical interest. Third, the data for the age group younger than 2 years are valuable, as this is the age group when the diagnosis of egg allergy is most often made for the first time. The diagnostic performance of BAT in this age group was impressive; however, the number of participants younger than 2 is limited to 25 children. Fourth, like any test, BAT is not absolute and there are patients with discrepant results when comparing the outcome of BAT and DBPCFC, as highlighted in Figure In summary, overall, BAT to egg was the best test to predict BE and LCE allergies and, out of tests currently available in clinical practice, the best test was sIgE to EW. SPT had a poorer diagnostic performance than anticipated. The addition of BAT to egg, for patients with equivocal results for sIgE to EW, added precision to the diagnosis and reduced the number of patients undergoing OFC compared to what we would have needed to clarify all equivocal cases, making the diagnostic process safer and more comfortable for patients. This greater precision and convenience can enable a more rigorous and accessible diagnostic approach and reduce over‐diagnosis due to over‐reliance on SPT or sIgE tests alone and to limited capacity for OFC. Further external validation is currently underway in a UK multicentre study (NCT05309772) to confirm the generalisability of our findings.