Appendicitis is the most common surgical emergency worldwide. Due to challenges in diagnosis there are still a considerable number of patients without appendicitis having unnecessary surgery for suspected appendicitis.

Diagnostic imaging with CT-scan has reduced unnecessary appendectomies, but using CT-scans in every patient with suspected appendicitis is costly, and may also be harmful in younger patients. Utilization of diagnostic imaging causes delay to surgery, which may increase the risk of perforation of appendix.

Diagnostic scoring provides a tool for categorizing patients with suspected appendicitis into three categories according to their probability of appendicitis. World Society of Emergency Surgery (WSES) guidelines suggests that risk stratification with clinical scoring may be useful in patients with suspected appendicitis.

Adult Appendicitis score (AAS) is developed and validated in adult patients, who were admitted to hospital emergency department with suspected acute appendicitis. AAS can identify over half of the patients with appendicitis into high probability group (AAS 16 or higher). These patients could be operated on without preoperative imaging with very low risk of unnecessary surgery. On the other hand, patients with low AAS (0-10) have very low probability of appendicitis, and the value of diagnostic imaging in these patients is limited. Patients with intermediate score (11-15) benefit most from diagnostic imaging. It has been shown, that number of unnecessary appendectomies has reduced significantly after introduction of protocol based diagnostic workup with AAS.