Diagnostic Accuracy of Sputum and Bronchoscopy-Guided Cytology Compared With Bronchial Biopsy in Pulmonary Lesions

Background: Bronchial biopsy remains the reference standard for diagnosing pulmonary pathology; however, minimally invasive cytological techniques are increasingly used in clinical practice. This study aimed to determine the diagnostic accuracy of sputum cytology, bronchoalveolar lavage (BAL) cytology, transbronchial needle aspiration (TBNA), and bronchial brush cytology in detecting malignant pulmonary lesions using bronchial biopsy as the reference standard, and to compare their relative diagnostic performance. Methods: A prospective observational study was conducted at Government Medical College, Datia, from March to September 2025. A total of 120 adult patients with clinical and radiological suspicion of pulmonary pathology underwent sputum cytology and bronchoscopy-guided sampling (BAL, TBNA, brush cytology), followed by bronchial biopsy. Histopathology served as the reference standard. Diagnostic performance parameters were calculated. Suspicious cytology results were considered positive for malignancy for sensitivity analysis. Results: Of 120 patients, 77 (64.2%) had malignant lesions on biopsy. TBNA cytology demonstrated the highest sensitivity (92.2%) and excellent diagnostic accuracy (area under the curve (AUC) 0.969), followed by brush cytology (sensitivity 85.7%, AUC 0.974). BAL cytology showed moderate sensitivity (71.4%, AUC 0.887), while sputum cytology had lower sensitivity (49.4%, AUC 0.808). All modalities showed statistically significant associations with histopathology (p < 0.001). TBNA and brush cytology exhibited superior concordance with biopsy findings compared with BAL and sputum cytology. Conclusion: Bronchoscopy-guided cytological techniques, particularly TBNA and brush cytology, demonstrate high diagnostic accuracy and strong concordance with bronchial biopsy findings. These modalities serve as valuable complementary diagnostic tools in selected clinical settings but do not replace histopathological confirmation.