Acute appendicitis is one of the most common surgical emergencies, and timely diagnosis is essential to prevent complications such as perforation, peritonitis, and unnecessary appendectomy. However, its diagnostic performance can vary according to operator expertise, patient characteristics, and visualization of the appendix. Histopathological examination of the removed appendix provides definitive confirmation of acute appendicitis and is commonly used as the reference standard. Objective: To determine the diagnostic accuracy of ultrasonography for detecting acute appendicitis by comparing preoperative ultrasonographic findings with postoperative histopathological examination as the gold standard. Methods: This diagnostic accuracy study included patients presenting with clinical suspicion of acute appendicitis who underwent abdominal ultrasonography followed by appendectomy. Ultrasonographic findings suggestive of appendicitis, including a non-compressible blind-ending tubular structure, increased appendiceal diameter, wall thickening, periappendiceal inflammation, and associated fluid collection, were recorded. Resected appendix specimens were subjected to histopathological examination. Results: Ultrasonography demonstrated useful diagnostic performance in identifying acute appendicitis. Published evidence using histopathology as the reference standard has reported variable sensitivity and specificity, reflecting differences in patient populations and operator expertise. A meta-analysis reported pooled sensitivity of approximately 77% and specificity of 60%, while other systematic reviews have demonstrated higher diagnostic performance in experienced settings. Conclusion: Ultrasonography is a valuable first-line imaging modality for suspected acute appendicitis and can provide clinically useful diagnostic information without radiation exposure. Nevertheless, because diagnostic accuracy may vary, equivocal ultrasonographic findings should be interpreted alongside clinical assessment and, when appropriate, further diagnostic evaluation. Histopathological examination remains an important reference standard for definitive confirmation. Keywords: Acute appendicitis; ultrasonography; abdominal ultrasound; diagnostic accuracy; histopathology; sensitivity; specificity; appendectomy.

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