Abstract
Background: Acute abdominal pain (AAP) is a common complaint of emergency department patients. An accurate diagnosis is even more crucial when AAP is associated with left lower quadrant (LLQ) pain, which has a wide variety of differential diagnoses from self-limiting to life-threatening diseases. This study aimed to evaluate the diagnostic efficacies of physical examination (PE), plain abdominal radiography (PAR), and ultrasonography (US) compared to the computed tomography (CT) scan in patients with nontraumatic LLQ AAP coming into the emergency department. Methods: This prospective cross-sectional study was performed on 220 patients with LLQ-AAP for > 2 h and < 5 days who underwent PAR, US, and CT after PE. An expert surgeon assigned a final diagnosis. Test characteristics, including diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative PV (NPV), were calculated for PE, PAR, and US, using a CT scan as the gold standard. Results: Among 220 patients (mean age of 48.17; 55.5% female), PE, PAR, and US yielded an overall accuracy of 30.91%, 35.91%, 50.91%, sensitivity of 75.47%, 62.26%, 39.62%, specificity of 16.77%, 27.54%, 54.49%, PPV of 22.35%, 21.43%, 21.65%, and NPV of 68.29%, 69.70%, and 73.98%, respectively. Conclusions: As a result of the highest sensitivity for PE and the highest accuracy for the US, we suggest considering PE as the primary investigation for identifying urgent conditions in patients with LLQ AAP and the US for an accurate diagnosis rather than PAR.