Background: Acute appendicitis remains one of the most common surgical emergencies. Elevated serum bilirubin levels have been proposed as potential markers in the diagnosis of acute appendicitis, particularly in distinguishing between uncomplicated and complicated cases.
The aim of the work: This study aimed to evaluate the role of elevated serum bilirubin levels in the diagnosis and differentiation of complicated versus uncomplicated acute appendicitis.
Patients and Methods: A total of 200 patients diagnosed with acute appendicitis based on clinical and radiological data were prospectively included in this study. All patients underwent appendectomy, and histopathological examinations of the excised appendices were conducted. The patients were classified into three groups: Group I (normal appendix, n=22), Group II (uncomplicated appendicitis, n=136), and Group III (complicated appendicitis, n=42). Serum bilirubin levels were measured preoperatively and analyzed in association with the histopathological findings.
Results: In Groups II and III, both WBCs and neutrophil ratios significantly increased, with mean values escalating from 12.58 to 17.26 for WBCs and from 64.37% to 81.58% for neutrophils across Groups I to III. Serum bilirubin and CRP levels also rose, showing significant associations with inflamed appendices. WBCs had the highest diagnostic accuracy (AUC 0.847) for differentiating inflamed from normal appendices, with the best sensitivity (69.1%) and specificity (90.9%). For complications, WBCs remained key, achieving sensitivities of 76.2% and specificities of 79.4%.
Conclusion:  Serum bilirubin is weaker than leucocytic count and CRP in the diagnosis of acute appendicitis, and in differentiating complicated from non-complicated cases. Nonetheless, it could be combined with these markers to enhance the diagnosis of that emergency surgical condition.