Assessment of Alvarado criteria, ultrasound, CRP, and their combination in patients with suspected acute appendicitis: a single centre study.

Background: Acute appendicitis (AA) is one of the most common reasons for visiting the emergency room. The lack of proper diagnosis and rapid treatment of AA may lead to severe complications such as intestinal perforation and increased mortality. This study aimed to evaluate the diagnostic accuracy of the Alvarado criteria, ultrasound, and CRP criteria in comparison with their combined use in patients with suspected AA who presented to the emergency room.

Methods: In this diagnostic accuracy study, 1411 patients with suspected AA who presented to the emergency department of Firoozabadi Hospital affiliated with Iran University of Medical Sciences and underwent appendectomy from October 2019 to October 2021 were examined. Nine hundred eighty-eight patients were enrolled. All patients were assessed using Alvarado, CRP, and ultrasound. The definitive diagnosis of AA was based on pathological findings and was considered the gold standard. Statistical analyses were performed with STATA VER 11.5. The diagnostic accuracy for each group was compared using the Pearson chi-square test. A value of p < 0.05 was considered statistically significant.

Results: The mean age was 29.57 ± 13.66 years. The sensitivity and specificity of Alvarado in the diagnostic accuracy of appendicectomy were 75.2% and 61.3% (CI = 95%), respectively. The sensitivity of ultrasound and CRP for predicting appendicitis was significantly higher than the Alvarado criteria. The diagnostic accuracy for CRP was significantly higher than ultrasound (64.9% vs. 60.7%, P: 0.003). The diagnostic accuracy of the simultaneous use of Alvarado + CRP and CRP + Ultrasound was significantly higher than that of Alvarado + ultrasound. The sensitivity, specificity, and diagnostic accuracy of the simultaneous use of all three criteria together (Alvarado + Ultrasound + CRP) were estimated to be 94.9%, 25.8%, and 81.5% (CI = 95%), respectively, which were significantly higher than the use of other criteria.

Conclusion: This study showed that the Alvarado criteria had inadequate diagnostic sensitivity and accuracy for diagnosing acute appendicitis. The diagnostic accuracy of acute appendicitis increases to over 90% using the three Alvarado, ultrasound, and CRP criteria at the same time.