[The value of bronchoalveolar lavage in the diagnosis of interstitial lung diseases].

Bronchoalveoläre lavage (BAL) allows microscopic, cytologic and immunocytologic diagnosis of alveolar and interstitial lung disease. The indications for BAL depend on chest X-rays, signs and symptoms and lung function tests, e.g., spirometry or whole-body plethysmography, CO-diffusion capacity and blood gases during exercise. Supporting laboratory parameters are angiotensin converting enzyme, antinuclear antibodies and serum precipitins. Pulmonary parenchymal pathology documented on chest X-rays or by high-resolution computed tomography of the chest allows selective investigation of the involved areas. Different typical patterns with predominantly neutrophils or lymphocytes and their subsets or the presence of malignant cells or Pneumocystis carinii in the BAL fluid allowed the diagnosis in 115 patients. If possible, histological confirmation should be achieved by transbronchial biopsy. When indications are carefully applied and are based on the history as well as the clinical signs and symptoms, BAL is an efficient diagnostic tool in interstitial lung disease, which can be performed in out-patients even if transbronchial biopsy is done.