Correlation between transbronchial lung biopsy and lung cytology

Respiratory diseases are an important cause of morbidity and mortality worldwide. Although conventional histopathology is the gold standard for their diagnosis, cytology is a useful adjunctive diagnostic test. In the present study we evaluated the efficacy of cytology in providing a rapid diagnosis. We included lesions which were both visible and not visible on bronchoscopy. We evaluated the role of bronchoalveolar lavage (BAL), brush cytology and imprint smears both separately and in combination, and compared them with the histopathological findings of transbronchial lung biopsy (TBLB). Among 100 cases the highest concordance was seen between imprint cytology (77.78%) and biopsy for malignancy, followed by bronchoalveolar lavage (40.91%) and brush cytology (40.00%). The concordance and level of agreement between cytology and biopsy was very poor in general for non-neoplastic lesions. However, it increased when BAL and imprint smears (42.50%) were performed together, compared to other combinations. We recommend a combination of cytological techniques in suspected cases of malignancy, as more useful than a single test, and to include imprint smears in all cases. However, biopsy remains the gold standard for diagnosis in non-neoplastic lung disease.