The Systemic Inflammatory Response Index as a Novel Diagnostic Tool for Acute Appendicitis.

Objective: This study aimed to assess the potential of the Systemic Inflammatory Response Index (SIRI) for diagnosing AA, its possible advantages over current methods, and its utility in distinguishing uncomplicated from complicated appendicitis. Methods: In this cross-sectional study, 240 patients scheduled for appendectomy with a diagnosis of AA were enrolled. Demographic information, clinical and paraclinical findings, including complete blood count (CBC), Alvarado score, SIRI, sonography findings, and pathology results, were documented. Data were analyzed using SPSS software version 26. Results: Of the 240 patients, 106 (44.2%) were men, and 134 (55.8%) were women, with a mean age of 37.49±15.55 years. Final pathology reports identified 26 (10.8%) cases of a normal appendix, 176 (73.3%) with uncomplicated appendicitis, 23 (9.6%) with complicated appendicitis, and 15 (6.3%) with reactive lymphoid hyperplasia. SIRI demonstrated significant differences across the pathology groups (P<0.0001). It showed notable discrimination between normal and complicated appendicitis (P=0.005), normal and combined appendicitis (P=0.008), and suggestive differences for normal versus uncomplicated (P=0.021) and uncomplicated versus complicated cases (P=0.044). Similarly, Alvarado scores showed significant differences, particularly between the normal and complicated appendicitis groups. Conclusion: The SIRI and Alvarado scoring systems showed significant potential for diagnosing appendicitis with acceptable sensitivity and specificity. They might also assist in differentiating between uncomplicated and complicated appendicitis.