title: A new 2-step risk-stratification clinical score for suspected appendicitis in children.
abstract: OBJECTIVE
  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'.
  
  
  CONCLUSIONS
  CAS is superior to PAS in ruling out appendicitis. Risk stratification of equivocal patients could guide the need for further diagnostic imaging examination.
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore. Electronic address: Yap.Te-Lu@kkh.com.sg.
authors.forename: Te-Lu
authors.initials: TL
authors.lastname: Yap
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore.
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore.
authors.forename: Wilson Wei Xin
authors.initials: WW
authors.lastname: Low
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore.
authors.forename: Caroline Choo Phaik
authors.initials: CC
authors.lastname: Ong
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore.
authors.forename: Shireen Anne
authors.initials: SA
authors.lastname: Nah
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore.
authors.forename: Anette S
authors.initials: AS
authors.lastname: Jacobsen
authors.affiliation: Department of Biostatistics, National University Health System, Singapore.
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore.
authors.forename: Yee
authors.initials: Y
authors.lastname: Low
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000293:Adolescent; D001064:Appendicitis / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D016015:Logistic Models; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: Appendicitis; Appendicitis score; C-reactive protein; Diagnosis; Pediatric; White blood cell count