Acute appendicitis is one of the most common surgical emergencies, but diagnostic uncertainty may still lead to unnecessary appendectomy in some patients. This prospective observational study aims to evaluate the diagnostic performance of computed tomography (CT) reporting and the Appendicitis Inflammatory Response (AIR) score in adult patients undergoing appendectomy for suspected acute appendicitis. The primary objective is to determine the negative appendectomy rate based on final histopathology. Secondary objectives are to assess the agreement between AIR score, CT findings, intraoperative severity grading, and pathology results, and to explore diagnostic performance across patient subgroups. No study-specific intervention beyond routine clinical care will be performed.

This is a single-center, prospective observational study conducted in adult patients presenting to the emergency department with suspected acute appendicitis. Patients aged 18 years or older who undergo computed tomography (CT) after clinical evaluation, have a CT report compatible with acute appendicitis, and subsequently undergo appendectomy will be eligible for inclusion. Patients younger than 18 years, pregnant patients or those with suspected pregnancy, patients taken directly to surgery without CT evaluation, patients whose CT report suggests a diagnosis other than acute appendicitis, patients requiring an additional non-appendectomy surgical procedure because of another intraoperative pathology, and patients who decline participation will be excluded.

Clinical and demographic data will be collected prospectively using a standardized study form. Recorded variables will include age, sex, comorbidities, previous abdominal surgery history, symptom duration, physical examination findings, and laboratory parameters relevant to appendicitis assessment. The Appendicitis Inflammatory Response (AIR) score will be calculated using routine clinical and laboratory data. CT examinations obtained as part of routine emergency care will be reviewed according to the official radiology reports. Intraoperative findings will be graded using the American Association for the Surgery of Trauma (AAST) appendicitis severity grading system. Final histopathologic examination of the resected appendix specimen will be used as the reference standard.

The primary outcome measure is the negative appendectomy rate, defined as appendectomy with final pathology not confirming acute appendicitis. Secondary outcome measures include agreement between AIR score and final pathology, agreement between CT report and final pathology, agreement between intraoperative AAST grading and final pathology, and differences in diagnostic performance across patient subgroups such as age, sex, and previous abdominal surgery history.

No study-specific intervention will be applied beyond routine diagnostic and therapeutic management. Treatment decisions will be made according to standard clinical practice. All data will be coded and recorded without directly identifiable patient information.

Inclusion Criteria:

• Age 18 years or older
• Presentation to the emergency department with suspected acute appendicitis
• Underwent computed tomography after clinical evaluation
• Computed tomography report compatible with acute appendicitis
• Underwent appendectomy for presumed acute appendicitis
• Provided informed consent

Exclusion Criteria:

• Age younger than 18 years
• Pregnancy
• Planned additional surgical intervention in the same session for a reason other than appendicitis
• Intraoperative finding of a non-appendiceal pathology requiring a different surgical procedure
• Refusal to participate in the study

Adult patients presenting to the emergency department with suspected acute appendicitis who undergo computed tomography after clinical evaluation, have a CT report compatible with acute appendicitis, and subsequently undergo appendectomy at Sanliurfa Education and Research Hospital.

Individual participant data will not be shared because this is a single-center study involving sensitive patient-level clinical data, and there is no pre-specified plan or institutional mechanism for external data sharing. Only aggregated, de-identified study results will be reported.