title: Diagnosing pediatric appendicitis: usefulness of laboratory markers.
abstract: OBJECTIVE
  This study aimed to evaluate the utility of C-reactive protein (CRP), procalcitonin (PCT), D-lactate, and white blood cell (WBC) count as an aid to distinguish appendicitis from other diagnoses.
  
  
  METHODS
  This prospective, observational study was conducted at an urban tertiary academic pediatric emergency department (ED). Subjects aged 1 to 18 years presenting with abdominal pain suspicious for acute appendicitis were enrolled. Data included history, physical examination, laboratory data (complete blood count, CRP, D-lactate, PCT [semiquantitative]), laboratory results, x-rays, surgical consultation notes, histopathology, and admission data. Stepwise logistic regression analysis was performed to identify independent risk factors.
  
  
  RESULTS
  Two hundred nine subjects (59% male, 41% female) were enrolled over 6 months. One hundred fifteen subjects were histologically diagnosed with appendicitis; 94 subjects did not have appendicitis and were used as controls. Mean values of WBC, CRP, PCT, and absolute neutrophil count in subjects with definitive appendicitis were significantly higher than in subjects with no definitive appendicitis. D-Lactate levels were noncorrelative. Significant independent risk factors identified for definitive appendicitis included WBC count more than 12 cells × 1000/mm(3) (adjusted odds ratio [AOR], 6.54), CRP level greater than 3 mg/dL (AOR, 3.44), presence of hopping pain (AOR, 2.69), and presence of pain with walking (AOR, 2.56). Odds ratio for definitive appendicitis and its 95% confidence interval was found to be 7.75 for subjects with both WBC more than 12 cells × 1000/mm(3) and CRP greater than 3 mg/dL.
  
  
  CONCLUSIONS
  C-reactive protein with WBC is useful in distinguishing appendicitis from other diagnoses in pediatric subjects presenting to the ED. White blood cell count greater than >12 cells × 1000/mm(3) and CRP greater than 3 mg/dL increases the likelihood of appendicitis. D-Lactate is not a useful laboratory adjunct.
authors.affiliation: Division of Emergency and Transport Medicine, Department of Pediatrics, Children's Hospital Los Angeles, University of Southern California and the Keck School of Medicine, Los Angeles, CA 90027, USA. kkwan@chla.usc.edu
authors.forename: Karen Y
authors.initials: KY
authors.lastname: Kwan
authors.forename: Alan L
authors.initials: AL
authors.lastname: Nager
mesh_terms: D015746:Abdominal Pain / Q000175:diagnosis; D000293:Adolescent; D001064:Appendicitis / Q000097:blood / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D019344:Lactic Acid / Q000097:blood; D007958:Leukocyte Count; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D012372:ROC Curve; D012307:Risk Factors
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D019344:Lactic Acid; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide