title: Hyperbilirubinaemia in appendicitis: the diagnostic value for prediction of appendicitis and appendiceal perforation.
abstract: OBJECTIVE
  The aim of this study is to evaluate the diagnostic value of pre-operative bilirubin levels in the diagnosis of acute appendicitis and appendiceal perforation.
  
  
  METHODS
  A retrospective analysis of 557 patients undergoing emergency appendicectomy over a 24-month period at a large teaching hospital. Hyperbilirubinaemia was defined as >25 µmol/L. Data were analysed using descriptive statistics.
  
  
  RESULTS
  484 of the 557 (86.9 %) operated cases were found histologically to be appendicitis. 116 cases of the 484 were perforated (24 %). Bilirubin levels were significantly higher in the group with appendicitis versus the group found to have a normal appendix at histology, [median (IQR) 12.0 µmol/L (9.00) vs. 8.0 µmol/L (7.00) respectively, p < 0.001], despite being within normal serum bilirubin range. Sensitivity of hyperbilirubinaemia for acute appendicitis was only 8 %, however specificity was 94 %. PPV was 85 % and NPV was 26 %. Whilst bilirubin was higher in patients with a perforated appendix versus acute appendicitis [median (IQR) 13.0 µmol/L (9.00) vs. 11.0 µmol/L (9.00), respectively], statistically, there was no significant difference in pre-operative bilirubin levels between the perforated appendicitis cases and the non-perforated appendicitis cases (p = 0.326). However, the specificity of hyperbilirubinaemia for perforated appendicitis was 93 %, sensitivity 9.4 %, PPV 24 % and NPV 82 %.
  
  
  CONCLUSIONS
  Bilirubin levels may be high, but remain within normal range, in cases of appendicitis. Therefore, bilirubin levels may be a useful measurement when investigating a patient with suspected appendicitis. Hyperbilirubinaemia is highly specific with regards to perforation, a finding supported by other studies. However, possibly because of the few perforated cases in this study, we cannot recommend that hyperbilirubinaemia be used to predict perforation.
authors.affiliation: Warwickshire Surgical Research Group, Warwickshire, UK. h.l.adams@doctors.org.uk.
authors.forename: H L
authors.initials: HL
authors.lastname: Adams
authors.affiliation: Warwickshire Surgical Research Group, Warwickshire, UK.
authors.forename: S S
authors.initials: SS
authors.lastname: Jaunoo
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D001062:Appendectomy / Q000379:methods / Q000706:statistics & numerical data; D001064:Appendicitis / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000209:etiology / Q000601:surgery; D001663:Bilirubin / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002648:Child; D005260:Female; D006801:Humans; D006932:Hyperbilirubinemia / Q000150:complications / Q000175:diagnosis; D008297:Male; D011237:Predictive Value of Tests; D057234:Preoperative Period; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D006113:United Kingdom
chemical_list: D015415:Biomarkers; D001663:Bilirubin
keywords: Appendicitis; Hyperbilirubinaemia; Perforated appendicitis