Appendicitis is the most common pediatric surgical emergency, although fewer than 1% of children presenting with acute abdominal pain have appendicitis.¹ Concern over morbidity from missed diagnoses may lead to unnecessary surgery or CT-related radiation exposure. In 2005, a clinical prediction rule was devised to identify children at low risk for appendicitis. It showed an NPV of 98% when none of the following features were present: absolute neutrophil count (ANC) ≤6.75 × 10³/μL, absence of nausea, and absence of maximal tenderness in the right lower quadrant (RLQ).² This study was conducted to further refine this rule.

To validate and refine a prediction rule that identifies children with acute abdominal pain at low risk for appendicitis.