Diagnostic value of basic laboratory parameters for simple and perforated acute appendicitis: an analysis of 3392 cases.

Background: The aim of the present study was to examine the efficacy of simple laboratory parameters including neutrophil-to-lymphocyte ratio (NLR), platelet count (PLT), mean platelet volume (MPV), and serum bilirubin level in the diagnosis of acute appendicitis and recognition of perforated appendicitis.

Methods: Records of 3392 patients who underwent appendectomy in a 10-year period were reviewed retrospectively. Patients were divided into 2 groups according to histopathological examination results: Group 1 had normal appendix, Group 2 had acute appendicitis. Patients with acute appendicitis were divided into subgroups: Group 2A had simple acute appendicitis, while Group 2B had perforated appendicitis. Efficacy of the aforementioned laboratory parameters was evaluated in the diagnosis of acute appendicitis and recognition of perforated appendicitis. Independent variables were determined by univariate analysis and multivariate analysis was performed. Receiver operating characteristic (ROC) curve analysis was used to identify significant parameters in multivariate analysis. Cut-off values, sensitivity, specificity, and accuracy calculations performed for parameters with area under curve (AUC) >0.600 were accepted as "significant parameters."

Results: White cell count (WCC), bilirubin, and NLR were significant parameters for the diagnosis of acute appendicitis. Cut-off values were 11900/mm3 for WCC (sensitivity: 71.2%; specificity: 67.2%; OR: 5.13), 1.0 mg/dl for bilirubin (sensitivity: 19.1%; specificity: 92.4%; OR: 2.96), and 3.0 for NLR (sensitivity: 81.2%; specificity: 53.1%; OR: 4.27). Serum bilirubin and NLR were independent variables for the diagnosis of perforated appendicitis. Cut-off values were 1.0 mg/dl for bilirubin (sensitivity: 78.4%; specificity: 41.7%; OR: 2.6) and 4.8 for NLR (sensitivity: 81.2%; specificity: 53.1%; OR: 2.6).

Conclusion: Presence of at least 1 of the following findings in a patient suspected of having acute appendicitis was significantly associated with a definite diagnosis: WCC >11.900 mm3, serum bilirubin >1.0 mg/dl, NLR >3.0. In patients with acute appendicitis, serum bilirubin >1.0 mg/dl or NLR >4.8 were significantly associated with the presence of perforation. While WCC is a significant parameter for diagnosis of acute appendicitis, no significant association with perforated appendicitis was found. PLT and MPV were not useful parameters when diagnosing acute appendicitis.