Correlation of Bronchoalveolar Lavage with Transbronchial and CT Guided Biopsy in Pulmonary Disease

Background: Bronchoalveolar lavage (BAL) is usually done in patients where clinical, radiological and routine investigations are not helpful in diagnosis. BAL cytology with histopathology can give definitive diagnosis in various diseases of lung. Aim: The aim of this study was to evaluate the diagnostic accuracy of BAL in pulmonary diseases when compared with endobronchial and CT guided lung biopsy. Material and Methods: A prospective study of 100 BAL samples over a period of two years (June 2017 to June 2019) was done in a tertiary care centre in Ahmedabad. Cytohistological correlation was done in all the cases with histopathological examination as “Gold Standard”. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of BAL was calculated. Results: BAL cytology revealed that out of the 100 cases, 61 cases were non-neoplastic, 13 cases were suspicious for malignancy and 26 cases were malignant while on histopathology, 29 cases were nonneoplastic, 69 cases were malignant and 2 cases were negative for any pathological lesion. BAL was concordant in 39 out of total 69 cases of lung cancer. BAL had a sensitivity of 56.5% and a very high specificity of 100% in detecting malignancy with a diagnostic accuracy of 70%. Conclusion: BAL cytology shows a moderate sensitivity in diagnosing pulmonary diseases, but it provides a very good specificity for malignant lesions. Thus, patients with conclusive BAL reports could reliably be started with appropriate interventions at an early stage of disease.