The value of hyperbilirubinaemia in the diagnosis of acute appendicitis

No reliably specific marker for acute appendicitis has been identified. Although recent studies have shown hyperbilirubinaemia to be a useful predictor of appendiceal perforation, they did not focus on the value of bilirubin as a marker for acute appendicitis. The aim of this study was to determine the value of hyperbilirubinaemia as a marker for acute appendicitis.

A retrospective analysis of appendicectomies performed in two hospitals (n=472). Data collected included laboratory and histological results. Patients were grouped according to histology findings and comparisons were made between the groups.

The mean bilirubin levels were higher for patients with simple appendicitis compared to those with a non-inflamed appendix (p<0.001). More patients with simple appendicitis had hyperbilirubinaemia on admission (30% vs 12%) and the odds of these patients having appendicitis were over three times higher (odds ratio: 3.25, p<0.001). Hyperbilirubinaemia had a specificity of 88% and a positive predictive value of 91% for acute appendicitis. Patients with appendicitis who had a perforated or gangrenous appendix had higher mean bilirubin levels (p=0.01) and were more likely to have hyperbilirubinaemia (p<0.001). The specificity of hyperbilirubinaemia for perforation or gangrene was 70%. The specificities of white cell count and C-reactive protein were less than hyperbilirubinaemia for simple appendicitis (60% and 72%) and perforated or gangrenous appendicitis (19% and 36%).

Hyperbilirubinaemia is a valuable marker for acute appendicitis. Patients with hyperbilirubinaemia are also more likely to have appendiceal perforation or gangrene. Bilirubin should be included in the assessment of patients with suspected appendicitis.