Abstract
BACKGROUND: Right iliac fossa (RIF) pain is a frequent and challenging presenting complaint in emergency departments, encompassing a wide spectrum of acute and chronic conditions. PURPOSE: To compare effectiveness of ultrasound versus initial clinical and lab tests for diagnosing acute appendicitis in patients with RIF pain, while also evaluating the impact of ultrasound operator experience as well as portable ultrasound system. MATERIALS AND METHODS: This retrospective study included 525 patients (aged ≥15 years) presenting with acute RIF pain to three emergency departments in Thi-Qar Governorate, Iraq (January 2024-January 2025). Sensitivity, specificity, predictive values (PPV and NPV), and accuracy for diagnosing acute appendicitis were calculated. Multivariable logistic regression identified independent predictors of diagnostic accuracy for both modalities. RESULTS: Among 525 patients, appendicitis was the final diagnosis in 273 (52.00%). For diagnosing acute appendicitis, ultrasound demonstrated significantly higher sensitivity (89.7% vs 67.4%), specificity (67.1% vs 46.4%), and overall accuracy (78.9% vs 57.3%) compared to clinical-laboratory assessment. Independent predictors of higher ultrasound accuracy included US operator experience (Senior EM Physician vs. Resident: aOR 3.15, 95% CI: 1.80-5.52) and presence of rebound tenderness (aOR 2.40, 95% CI: 1.35-4.27). For clinical-laboratory assessment, ED physician experience (Senior vs. Resident: aOR 1.48, 95% CI: 1.15-2.41) was one of the independent predictors of higher accuracy. CONCLUSION: Ultrasound significantly outperforms initial clinical-laboratory assessment in diagnosing acute appendicitis among patients with RIF pain in this setting. US operator experience is a key determinant of ultrasound accuracy. Our findings support the effective use of portable ultrasound systems in the emergency setting.