Evaluating the diagnostic utility of the slide agglutination method for brucellosis in Saudi Arabia: A retrospective study at International Medical Center, Jeddah, Saudi Arabia.

Background: Brucellosis, a prevalent zoonotic disease in endemic regions like Saudi Arabia, poses diagnostic challenges due to its nonspecific clinical manifestations. This disease is endemic in various regions, including the Mediterranean basin, the Middle East, Asia, Africa, and Latin America. This retrospective study is designed to evaluate the diagnostic utility of the slide agglutination method for brucellosis. By examining its sensitivity, specificity, and overall performance, this research will provide insights into the reliability of the slide agglutination method as a diagnostic tool in a high-prevalence setting.

Methods: This retrospective study, conducted at the International Medical Center, Jeddah, compared the real-world diagnostic performance of the Slide Agglutination Method (SAM) with gold-standard blood cultures and Brucella serology. Over 734 cases (37 Brucella-positive and 697 Brucella-negative) were reviewed between 2019 and 2022.

Results: SAM achieved 86.5% sensitivity and 99.3% specificity, with an average turnaround time of 2.32 hours. In contrast, blood culture showed 40.9% sensitivity and 94.5% accuracy, and conventional serology demonstrated comparable sensitivity but longer processing times.

Conclusion: SAM combines speed, simplicity, and robust accuracy, making it an ideal first-line screen for acute brucellosis in endemic, resource-limited settings. However, its performance in chronic or low-titer infections remains less well characterized. Our detailed operational metrics fill a local evidence gap and support the Saudi Ministry of Health in updating national screening guidelines.