International normalized ratio and serum C-reactive protein are feasible markers to predict complicated appendicitis.

Background: Diagnostic approach for complicated appendicitis is still controversial. We planned this study to analyze preoperative laboratory markers that may predict complications of appendicitis.

Methods: Patients who underwent appendectomy were retrospectively recruited. They were divided into complicated appendicitis and non-complicated appendicitis groups and their preoperative laboratory results were reviewed.

Results: A total of 234 patients were included. Elevated international normalized ratio (INR) and serum C-reactive protein (CRP) were associated with complicated appendicitis (p = 0.001). On ROC curve analysis, area under the curve (AUC) of CRP and INR were 0.796 and 0.723, respectively.

Conclusions: INR and CRP increased significantly in patients with complicated appendicitis. Further studies evaluating INR and CRP in patients undergoing conservative management for appendicitis are required.