Objectives: The objective was to characterize the variations in practice in the diagnosis and management of children admitted to hospitals from Canadian pediatric emergency departments (EDs) with suspected appendicitis, specifically the timing of surgical intervention, ED investigations, and management strategies.Methods: Twelve sites participated in this retrospective health record review. Children aged 3 to 17 years admitted to the hospital with suspected appendicitis were eligible. Site-specific demographics, investigations, and interventions performed were recorded and compared. Factors associated with afterhours surgery were determined using generalized estimating equations logistic regression.Results: Of the 619 children meeting eligibility criteria, surgical intervention was performed in 547 (88%). After-hours surgery occurred in 76 of the 547 children, with significant variation across sites (13.9%, 95% confidence interval = 7.1% to 21.6%, p < 0.001). The overall perforation rate was 17.4% (95 of 547), and the negative appendectomy rate was 6.8% (37 of 547), varying across sites (p = 0.004 and p = 0.036, respectively). Use of inflammatory markers (p < 0.001), blood cultures (p < 0.001), ultrasound (p = 0.001), and computed tomography (p = 0.001) also varied by site. ED administration of narcotic analgesia and antibiotics varied across sites (p < 0.001 and p = 0.001, respectively), as did the type of surgical approach (p < 0.001). After-hours triage had a significant inverse association with after-hours surgery (p = 0.014).Conclusions: Across Canadian pediatric EDs, there exists significant variation in the diagnosis and management of children with suspected appendicitis. These results indicate that the best diagnostic and management strategies remain unclear and support the need for future prospective, multicenter studies to identify strategies associated with optimal patient outcomes.ACADEMIC EMERGENCY MEDICINE 2015;22:811-822 © 2015 by the Society for Academic Emergency Medicine A ppendicitis is the most common nontraumatic surgical emergency in children, 1,2 yet it continues to present diagnostic and management uncertainty.3 Current strategies for diagnosing appendicitis include the use of clinical scoring systems, 4-7 laboratory markers of infection and inflammation, [8][9][10] and