Pediatric Appendicitis Score Age Range
The Pediatric Appendicitis Score (PAS) is validated and used in children aged 4 to 15 years, though some studies have extended its application up to 18 years. 1
Original Validation and Age Range
The PAS was originally developed and validated by Samuel in 2002 in a prospective study of 1,170 children aged 4 to 15 years with abdominal pain suggestive of acute appendicitis. 1
This original derivation study established the score's diagnostic performance with a sensitivity of 1.0, specificity of 0.92, positive predictive value of 0.96, and negative predictive value of 0.99 in this age group. 1
Extended Age Applications in Clinical Practice
Subsequent validation studies have tested the PAS in broader pediatric age ranges, with some studies including patients aged 3 to 21 years to evaluate its performance across the entire pediatric spectrum. 2
A 2019 Iranian validation study specifically evaluated the PAS in children under 18 years and found diagnostic accuracy of 91% with sensitivity of 93.88% and specificity of 86.21% at a cutoff of 5.5. 3
A Canadian validation study in 2009 enrolled children aged 4 to 18 years presenting to a pediatric emergency department, demonstrating that the score maintained utility across this extended age range. 4
Important Age-Related Performance Considerations
The PAS performs less reliably in preschool-aged children (younger than school age), who often present with atypical features, more rapid progression, and higher complication rates. 5
Children of preschool age are more likely to have lower PAS and Alvarado scores compared to school-aged children, even when appendicitis is present. 5
The 2020 WSES Jerusalem Guidelines note that the AIR score outperformed both the PAS and Alvarado score in a study of 747 children with a mean age of 11 years, suggesting that alternative scoring systems may be preferable in certain pediatric populations. 5
Practical Clinical Application
For optimal diagnostic accuracy, the PAS should be primarily used in children aged 4 to 15 years, with cautious interpretation in younger preschool children and awareness that performance may vary in older adolescents approaching 18 years. 1, 3
The score includes eight variables specifically relevant to children: cough/percussion/hopping tenderness in the right lower quadrant (2 points), anorexia (1 point), pyrexia (1 point), nausea/emesis (1 point), right iliac fossa tenderness (2 points), leukocytosis (1 point), polymorphonuclear neutrophilia (1 point), and migration of pain (1 point), for a total possible score of 10. 1
The 2020 WSES Jerusalem Guidelines recommend against making a diagnosis of acute appendicitis in pediatric patients based on clinical scores alone, regardless of age, emphasizing that imaging and clinical judgment must supplement scoring systems. 5