The diagnosis of acute appendicitis remains a challenge in daily clinical practice. The high incidence of appendicitis drives the need to reduce morbidity and unnecessary costs due to negative appendectomies. The aim of the present observation study is to evaluate a diagnostic and therapeutic algorithm for suspected acute appendicitis.

The investigators believe that this diagnostic algorithm helps to simultaneously avoid unnecessary operations, costs and radiation exposure.

This prospective observation study will be performed in the university hospital Frankfurt with a 24-h emergency service, with surgery and radiology readily available. The data will be compiled on patients older than 18 years who will be admitted to the emergency unit with suspected appendicitis.

During the study period, the clinical workflow is standardized. In all cases a resident of surgery and/or consultant surgeon clinically evaluate and perform an ultrasound scan on all patients with suspected appendicitis. With the use of clinical and laboratory results the physician (surgeon) will calculate the Alvarado Score and depending on the result the next diagnostic steps or the treatment will be chosen. Additionally, the department of gynecology of the university hospital routinely evaluate all women of childbearing age. Upon other terms following variables will be collected: age, gender, white blood cells (WBC), C-reactive protein (CRP), Alvarado Score, visuell pain scale, CT scan results, pathologic findings, time between admission and operation, operation procedure, treatment and diagnosis of patients without operation, length of hospital stay, and 30-day complication rate. Furthermore, there will be a follow-up of all patients (with and without operation) after 30 days and 6 months.

The investigators assume that the use of a diagnostic and therapeutic algorithm reduces unnecessary negative appendectomies and optimizes the duration of the hospital stay and the costs.

Inclusion Criteria:

• complete evaluation, examination and diagnostic pathways of the patients with suspected appendicitis in our University Hospital

Exclusion Criteria:

• appendectomy during other operations

Patients admitted to our University department with suspected appendicitis and/or lower right abdominal pain.