Evaluation and comparison of the results of the Alvarado scoring system with acute inflammatory response score in the diagnosis of acute appendicitis based on the pathological evidence

Introduction: Although appendectomy is the most common reason for abdominal surgery, acute appendicitis (AA) diagnosis remained a challenging issue using various scoring systems. Objectives: The current study aims to investigate the diagnostic value of the Alvarado scoring system versus the acute inflammatory response score (AIRS) in the diagnosis of AA. Patients and Methods: The current cross-sectional study was conducted on 120 patients who underwent appendectomy between 2019 and 2020. The on-admission Alvarado and AIRS scores were evaluated for the patients. Besides, the histopathological study of the resected tissues was considered the gold standard. The receiver operating characteristics (ROC) curve was depicted for the scoring systems, and sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV), and area under the curve (AUC) were calculated. Results: The sensitivity, specificity, NPV, and PPV of Alvarado criteria for scores >4 equaled 89.3%, 23.5%, 35.2%, and 89.3%, respectively. These amounts were calculated as 96.1%, 82.3%, 77.7%, and 97% for the AIRS, respectively. Moreover, at cut-points >8, the sensitivity of 32.1%, specificity of 100%, PPV of 100%, and NPV of 15.7% have been measured for AIRS compared with 41.7%, 88.2%, 97.1%, and 29.4% for Alvarado, respectively. The measured AUC for AIRS and Alvarado criteria accounted for 0.81 and 0.72, respectively (P value <0.05). Besides, 17 (14.16%) ones had a negative appendectomy. Conclusion: Based on the current study's findings, both AIRS and Alvarado scoring systems were reliable means to diagnose appendicitis; however, AIRS was relatively superior considering its higher specificity and PPV in scores >8 and higher sensitivity and NPV in scores >4.