Background: Various imaging tests as well as different scoring systems based on symptoms, signs and laboratory findings are commonly used to improve diagnostic accuracy in acute appendicitis. The aim of this study was to compare the diagnostic accuracy of MANTRELS scoring system (designed by Alfredo Alvarado), which is based on symptoms, signs and laboratory results, with sonographic findings.

Methods: In this prospective observational study, 106 patients with acute abdomen suspicious of acute appendicitis at Sina Hospital, Isfahan, Iran, were studied from March 2004 to February 2006.

Results: The disease was most common in patients aged 20-29 years, with male predominance. All patients had appendectomies. One hundred patients had acute appendicitis and six had negative appendectomy. Among the patients with acute appendicitis, 88% had an Alvarado score of ≥6 and 12% had a score of ≤5. Among the six patients with negative appendectomy, 66.7% had Alvarado scores of ≤5 and 33.3% had scores of ≥6, which was significantly different (p=0.005). The sonographic results were abnormal in 71.9% of patients with acute appendicitis and in 25% of patients with negative appendectomy, which was not significantly different (p=0.08). In our study, the diagnostic accuracy of an Alvarado score ≥6 was 88% and that of the sonographic results was 71.9% for acute appendicitis. If the Alvarado score ≥6 and abnormal sonographic findings are considered together, the diagnostic accuracy improves to 97.2%.