Outsourced CT Reporting versus Clinical Assessment for Diagnosing Acute Appendicitis: A Retrospective Diagnostic Accuracy Study

Background Outsourced radiology interpretation is increasingly used to maintain emergency imaging workflows, yet its diagnostic performance in suspected acute appendicitis remains uncertain. We compared outsourced non-contrast CT reporting with bedside clinical assessment in a surgically managed cohort. Methods This retrospective diagnostic accuracy study included adults (≥ 18 years) who underwent appendectomy for suspected acute appendicitis. Index tests were outsourced CT reports and the attending surgeon’s preoperative clinical assessment. The reference standard was intraoperative and/or histopathological diagnosis. Sensitivity, specificity and accuracy were calculated with 95% confidence intervals. Results Among 573 patients, appendicitis was confirmed in 492 (85.9%) and negative appendectomy occurred in 81 (14.1%). Outsourced CT reporting yielded sensitivity 87.4% (95% CI 84.1–90.1), specificity 75.3% (95% CI 64.8–83.6) and accuracy 91.4%. Clinical assessment yielded sensitivity 97.6% (95% CI 95.8–98.6), specificity 54.3% (95% CI 43.6–64.5) and accuracy 85.7%. Conclusions In this cohort, outsourced non-contrast CT reports showed higher specificity than clinical assessment, but clinically meaningful false-positive reporting may contribute to potentially avoidable appendectomies. Quality assurance and standardized protocols may improve performance in outsourced services. Trial registration: Not applicable.