The utility of bronchoalveolar lavage in the evaluation of interstitial lung diseases: A clinicopathological perspective.

Bronchoalveolar lavage (BAL) is a noninvasive and well-tolerated procedure that is performed with a fiberoptic bronchoscope in the wedged position within a selected bronchopulmonary segment. After it was introduced to clinical practice, BAL rapidly gained acceptance in a large number of centers as a procedure that could be applied to the clinical evaluation of patients with various pulmonary disorders, especially the group of interstitial lung diseases (ILD). Cytological and flow cytometric analysis of BAL fluid in ILD is done with knowledge of the clinical presentation and radiological findings. BAL typically reveals variations in the types and numbers of nucleated immune cells and acellular components in patients with ILD, which differ from those seen in normal control subjects. Many clinicians currently use this technique as a guide in the differential diagnoses of ILD; it can also be used to monitor the course of disease and possible response to therapeutic interventions. This article summarizes current clinicopathological information concerning the use of BAL by pulmonologists and pathologists.