Evaluating the Accuracy of Appendicitis Inflammatory Response and Alvarado Scoring Systems in Predicting Acute Appendicitis

Background: Diagnosis of acute appendicitis (AA) is usually clinical, but the high negative appendectomy rates necessitated the development of several scoring systems. This study compares the accuracy of the conventional Alvarado with the newer appendicitis inflammatory response (AIR) scoring systems in the diagnosis of appendicitis. Materials and Methods: Patients with AA who had been selected for appendectomy by surgeons were evaluated pre-operatively using the Alvarado and AIR scoring systems with histopathological diagnosis as the benchmark. Both systems classified patients into low-, intermediate-, and high-risk groups. Results: Fifty-two patients with a mean age of 26.1 SD ± 10.1 years were evaluated. The negative appendectomy rate was 15.4%. Both systems had low sensitivity scores, with Alvarado performing slightly better, with a sensitivity of 45% vs. 30% (AIR). However, the two scoring systems showed remarkable specificity and a positive predictive value of 100% but performed poorly in the intermediate group, with all 24 patients classified as intermediate by AIR and 17 of the 18 classified by Alvarado as having histologically confirmed appendicitis. Notably, most patients in the indeterminate group had elevated C-reactive protein (CRP) levels. Conclusion: The two scoring systems show similar strengths in correctly predicting low- and high-risk patients. Patients classified as intermediate by both scoring systems with elevated CRP levels (>10 g/L) should be strongly considered positive. Modification of the clinical parameters of the AIR score may improve its diagnostic accuracy and clinical utility, hence reducing negative appendectomy rates.