not-yet-known not-yet-known not-yet-known unknown Abstract Background: Peanut allergy (PA) is a significant health concern. Children with a relatively low reaction threshold PA have an increased risk of accidental life-threatening reactions, compared to those with a higher threshold. Diagnostic and treatment protocols for high threshold PA are also safer and easier to implement. Our study aims to identify clinical factors determining the reaction threshold in PA children. Methods: A retrospective study, collecting and analyzing data of challenge-proven PA children under 12 years of age, from our pediatric food allergy center, where all children with suspected PA are offered a diagnostic challenge. The data included demographics, medical history, skin test and oral food challenge results. Results: A total of 202 children under 12 years of age (mean 42 months, 95% CI 38-46) with challenge-proven PA were enrolled in the study. Children with low threshold PA (threshold less than 100mg) were more likely to be older than 4 years (43.6% Vs 21.7%, p < 0.001). In a gender subanalysis we found girls had additional influencing factors such as previous systemic/anaphylactic reaction (p<0.001). In a decision tree analysis, the major modifiable risk factor was a diagnosis at a young age. Conclusion: Since an oral food challenge is the gold standard for the diagnosis of PA, performing a diagnostic challenge at a young age, optimizes our chance to diagnose PA with a relatively high threshold, increasing the safety and outcomes of potential interventions. Therefore, the early referral of young patients for a diagnostic workup is mandated.