Abstract
Background: Multiple scoring systems have been developed in order to identify patients who need emergency appendicectomy and those who are unlikely to have acute appendicitis.RIPASA and Alvarado scoring systems are two of these systems. The aim of this article was to compare both systems in terms of diagnostic accuracy.
Methods: The study was carried out in the period from August 2010 to January 2012.RIPASA and Alvarado scores were performed for all patients above 14 years in whom decision to operate was already made by independent surgeons. Sensitivity,specificity,predictive values and accuracy were calculated. Data analyzed using SPSS 16 and STATA 11.
Results: 600 patients were included with mean age 26.52 years. Negative appendicectomy rate was 17%.Sensitivity for RIPASA and Alvarado scores were 93.2 and 73.7,respectively(P value<0.001).RIPASA accuracy(91.5) was significantly higher than Alvarado score accuracy(74.3).Predicted negative appendicectomy rates for RIPASA and Alvarado systems were 7.8% and 8%,respectively(P value=0.88).
Conclusion: Both RIPASA and Alvarado scoring systems could significantly lower negative appendicectomy rate.However,RIPASA could identify a significant proportion of patients who would be otherwise missed by Alvarado score.

Key words: Acute appendicitis, negative appendicectomy, RIPASA score, Alvarado score