title: Usefulness of new and traditional serum biomarkers in children with suspected appendicitis.
abstract: OBJECTIVE
  The objective of the study is to evaluate the usefulness of the leukocyte (white blood count [WBC]) and neutrophil (absolute neutrophil count [ANC]) counts; the values of C-reactive protein (CRP), procalcitonin, and calprotectin (CP); and the APPY1 Test panel of biomarkers, to identify children with abdominal pain at low risk for appendicitis.
  
  
  METHODS
  Children 2 to 14 years of age with abdominal pain suggesting acute appendicitis (AA) were prospectively included. Procalcitonin, calprotectin, C-reactive protein, white blood count, ANC, and the new plasma APPY1 Test were performed. The final diagnosis was determined by histopathology in cases of AA and telephone follow-up in children discharged without AA.
  
  
  RESULTS
  Between February 2012 and June 2013, 185 children were enrolled with an average age of 9.32±2.7 years. Eighty-nine (48.1%) were finally diagnosed with AA. The APPY1 Test panel showed the highest discriminatory power, sensitivity of 97.8 (95% confidence interval [CI], 92.2-99.4), negative predictive value of 95.1 (95% CI, 83.9-98.7), negative likelihood ratio of 0.06 (95% CI, 0.01-0.22), and specificity of 40.6 (95% CI, 31.3-50.5). A negative APPY1 Test and ANC less than 7500 per milliliter provided a sensitivity of 100 (95% CI, 95.9-100), negative predictive value of 100 (95% CI, 89.8-100), and specificity of 35.4 (95% CI, 26.6-45.4). In the multivariate analysis, only the APPY1 Test and ANC greater than 7500 per milliliter were significant risk factors for AA (odds ratio, 13.76; 95% CI, 3.02-62.57, and odds ratio, 6.37; 95% CI, 2.89-14.28, respectively).
  
  
  CONCLUSIONS
  The APPY1 Test panel with ANC could be useful in identifying children with abdominal pain suggestive of AA who are at low risk for this disease.
authors.affiliation: Pediatric Emergency Department, Cruces University Hospital, Bilbao, Basque Country, Spain. Electronic address: javier.benitof@osakidetza.net.
authors.forename: J
authors.initials: J
authors.lastname: Benito
authors.affiliation: Pediatric Emergency Department, Cruces University Hospital, Bilbao, Basque Country, Spain.
authors.forename: Y
authors.initials: Y
authors.lastname: Acedo
authors.affiliation: Pediatric Surgery Department, Cruces University Hospital, Bilbao, Basque Country, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Medrano
authors.affiliation: Pediatric Emergency Department, Cruces University Hospital, Bilbao, Basque Country, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Barcena
authors.affiliation: Laboratory Department, Cruces University Hospital, Bilbao, Basque Country, Spain.
authors.forename: R Perez
authors.initials: RP
authors.lastname: Garay
authors.affiliation: Epidemiologic Unit, Cruces University Hospital, Bilbao, Basque Country, Spain.
authors.forename: E Arana
authors.initials: EA
authors.lastname: Arri
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; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D039841:Leukocyte L1 Antigen Complex / Q000097:blood; D016015:Logistic Models; D008297:Male; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D039841:Leukocyte L1 Antigen Complex; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide