Validation of the Appendicitis Inflammatory Response (AIR) Score in Diagnosing and Classifying Acute Appendicitis: A Prospective Study at a Tertiary Hospital in Bengaluru, India

Introduction: Acute appendicitis is a common abdominal emergency that often requires hospital care and urgent surgery. Diagnosis can be difficult, which sometimes results in unnecessary operations. To improve accuracy and reduce avoidable procedures, scoring systems, such as the Appendicitis Inflammatory Response (AIR) score, have been developed, using clinical features and inflammatory markers to guide risk stratification. This study evaluates the AIR score for its ability to distinguish between uncomplicated and complicated cases, rule out non‑appendicitis conditions, and reduce reliance on unnecessary admissions, imaging, and surgery. Methods: A prospective observational study was conducted at Kempegowda Institute of Medical Sciences and Research Centre, Bengaluru, India, including 100 patients aged ≥ 18 years presenting with right lower quadrant pain, suggestive of appendicitis. Patients were stratified into low, intermediate, and high-risk groups based on the AIR score. Management was tailored accordingly: low scores received outpatient follow‑up, intermediate scores were reassessed with possible imaging or laparoscopy, and high scores underwent immediate surgery. Outcomes included sensitivity, specificity, predictive values, and secondary measures such as negative appendectomy rate. Results: AIR score ≥ 4 demonstrated sensitivity of 85.9%, specificity of 100%, PPV of 100%, and NPV of 80% (AUC: 0.94) for diagnosing appendicitis. AIR score ≥ 8 showed sensitivity of 85.7%, specificity of 97.6%, positive predictive value (PPV) of 94.7%, and negative predictive value (NPV) of 93.3% (AUC: 0.94) for complicated appendicitis. Negative appendectomy was significantly reduced when the AIR score was applied. Conclusion: The AIR score is a reliable diagnostic tool for appendicitis, outperforming traditional scoring systems. Its use can reduce unnecessary surgeries, hospital admissions, and imaging, thereby improving patient outcomes and resource utilization.