Acute inflammatory response and Alvarado scoring systems in the diagnosis of acute appendicitis: which one is more accurate?

BACKGROUND: Acute appendicitis remains one of the most common causes of acute abdomen requiring early appendectomy. Despite advances in diagnostic techniques, negative appendectomies are still performed. Alvarado Score is the most common and widely applied scoring system without using reactive protein (CRP). Recently introduced appendicitis inflammatory response (AIR) scores with applying CRP overcome this drawback; however, the accuracy of both scores in the diagnosis of appendicitis in Asian populations, is not well defined. The aim of this study was to compare the Appendicitis Inflammatory Response Score to the traditional Alvarado Score to determine which is more accurate in the diagnosis of acute appendicitis in Iranian population. METHODS: This study was performed on 130 patients who presented with right quadrant pain and with suspected appendicitis. Before surgery, demographic data AIRS and Alvarado Score were recorded for all patients; the comparison of two scoring methods was made considering the correlation of the scores with final histopathology report. The sensitivities, specificities, positive and negative predictive values, positive and negative likelihood ratios for both systems were determined, and t-test, chi(2) and receiver operating characteristic curve (ROC) was used to analyze the data. RESULTS: At the optimal cut-off point of >5.5 for the Alvarado Score, the sensitivity and the specificity were 96.2% and 84%; for the AIR score the optimal cut-off point was >4.5, sensitivity and specificity were 98.1% and 92%, respectively. The positive and negative predictive values of the Alvarado Score were 86.27% and 39.2%; in AIR score predictive values were 86% and 36.66 respectively. The positive negative likelihood ratio values of the Alvarado Score were 1.49 and 0.36; for AIR the positive and negative values were 1.46 and 0.41respectly. Final positive appendectomy was 105 (80.8%) and negative appendectomy was 25 (19.2%) in histopathology report. CONCLUSIONS: Both scoring systems have similar accuracy in ruling out of acute appendicitis.