Prospective validation of the pediatric appendicitis score.
OBJECTIVE
To prospectively validate the Pediatric Appendicitis Score (PAS), developed on a cohort of children with abdominal pain suggestive of appendicitis, in unselected children with abdominal pain who present to the emergency department.


STUDY DESIGN
Over a 19-month period, we prospectively recruited children 1 to 17 years old who came to our tertiary pediatric emergency department, with a chief complaint of abdominal pain of duration less than 7 days. PAS components included fever >38 degrees C, anorexia, nausea/vomiting, cough/percussion/hopping tenderness (2 points), right-lower-quadrant tenderness (2 points), migration of pain, leukocytosis >10 000 cells/mm(3), and polymorphonuclear neutrophilia > 7500 cells/mm(3). A follow-up call was made to verify final outcome. Sensitivity, specificity, and the receiver operating characteristic curve of the PAS with respect to diagnosis of appendicitis were calculated.


RESULTS
We collected data on 849 children. 123 (14.5%) had pathologic study-proven appendicitis. Mean (median, range) score for children with appendicitis and without appendicitis was 7.0 (7, 2-10) and 1.9 (1, 0-9), respectively. If a cutoff PAS of <or=2 was used to discharge patients without further investigation, only 3 (2.4%) with appendicitis would be sent home. If a PAS of >or=7 was used to take children to the operating room without further investigation, only 29 (4%) would not have appendicitis. For the PAS the area under the receiver operator curve was 0.95.


CONCLUSIONS
The PAS is useful, because a value <or=2 (found in 73% of children without appendicitis) has high validity for ruling out appendicitis, and a score >or=7 (found in 61% of children with appendicitis) has a high validity for predicting the presence of appendicitis. Children with PAS of 3 to 6 (37% with appendicitis and 23% without appendicitis in this study) should undergo further investigation such as observation, ultrasonography, or computed tomography.