Comparative Diagnostic Yield of Cytology, Imprint Cytology, and Histopathology in Medical Thoracoscopic Pleural Biopsies: A Prospective Observational Study.

Background Pleural effusion is a common clinical problem with varied etiologies. Timely diagnosis is essential for appropriate treatment. This study aimed to compare the diagnostic performance of brush cytology and imprint cytology, with histopathology, in pleural biopsy specimens obtained via thoracoscopy. Methods This prospective observational study included 96 patients with undiagnosed exudative pleural effusion undergoing medical thoracoscopy. Biopsy samples were analyzed by histopathology, brush cytology, and imprint cytology. Diagnostic metrics, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), McNemar's test, receiver operating characteristic (ROC) analysis, and logistic regression, were computed. Results Imprint cytology demonstrated higher sensitivity (73.17%) and NPV (76.60%) compared to brush cytology (65.85% and 72.00%, respectively). Logistic regression showed that a positive imprint result predicted biopsy positivity with an odds ratio of 5.17. ROC analysis confirmed superior diagnostic performance for imprint cytology. Conclusion Imprint cytology is a reliable, rapid, and effective diagnostic tool in thoracoscopic pleural biopsy evaluation, with performance metrics approaching those of histopathology.