Revisiting a Prediction Rule for Identifying Children at Low Risk for Appendicitis

A previously published prediction rule developed at a single center classifies children as having low risk for appendicitis if they meet the following criteria: absolute neutrophil count ≤6.75 x 10³/µL, absence of nausea, and absence of maximal tenderness in the right lower quadrant (RLQ). The rule yielded a sensitivity of 98% and specificity of 32%. Now, the investigators validated and refined the rule in a prospective cohort of 2625 children (age range, 3 to 18 years; mean, 11 years) who presented to 9 pediatric emergency departments during 1 year with abdominal pain of <96 hours duration and suspected appendicitis.

Overall, 1018 patients (39%) were diagnosed with appendicitis, and of these, 275 (27%) had a perforated appendix. Computed to…