The values of laboratory examinations which are useful for the diagnoses of appendicitis are white blood cell count (WBC), C-reactive protein (CRP) and erythrocyte blood sedimentation rate (ESR). However up to date there is no laboratory marker for the pre-operative diagnosis of appendiceal perforation in acute appendicitis. Recently hyperbilirubinaemia has been associated with appendiceal perforation. Aim of this retrospective study is therefore to investigate if hyperbilirubinaemia has a diagnostic value for the pre-operative diagnosis of appendiceal perforation in patients with appendicitis.