A new 2-step risk-stratification clinical score for suspected appendicitis in children.

AIM: The aim of this study was to develop a new Children's Appendicitis Score (CAS) by combining 3 inflammatory markers and a set of predictors for suspected appendicitis in children.

METHODS: 374 children aged 4-16years with suspicion of appendicitis were prospectively enrolled for the derivation cohort. Demographic characteristics, clinical features, laboratory, and histology data were collected. The outcome measure was the histological presence or absence of appendicitis. Backward logistic regression was employed to select predictors for construction of a score. Diagnostic performance of CAS was compared with the Pediatric Appendicitis Score (PAS) on a separate validation cohort.

RESULTS: The combination of normal white blood cell count (WBC), neutrophil percentage, and C-reactive protein (CRP) had a 100% negative predictive value for appendicitis. We assigned 'coefficient A' as 'zero' when all triple markers were negative and 'one' when any one markers was positive. A second component of 6 predictors was identified for construction of the 'raw score': Localized right-lower-quadrant pain, generalized guarding, constant characteristic of pain, pain on percussion or coughing, WBC≥14000/L and CRP≥24g/L. CAS was generated by multiplying 'coefficient A' by 'raw score'.

CONCLUSION: CAS is superior to PAS in ruling out appendicitis. Risk stratification of equivocal patients could guide the need for further diagnostic imaging examination.