[Contribution of bronchoalveolar lavage to the management of interstitial lung disease].

Bronchoalveolar lavage (BAL) is a minimally invasive method for exploring the distal lung. It enables collection of free cellular and acellular material present in the alveoli. Over the last two decades BAL has become a fundamental tool for positive diagnosis of interstitial lung disease and even more for differential diagnosis. It has contributed greatly to the diagnosis of lung infections, particularly in immunosuppressed patients. In the context of non-infectious infiltrative disease, the diagnostic contribution of BAL is limited due to the lack of a specific cell profile. It remains a fundamental tool for the differential diagnosis of idiopathic interstitial pneumonia. With BAL, a number of infectious or tumoral diseases can be ruled out with precision. It is also an important element for the evaluation of possible iatrogenic disease. BAL has transformed the diagnosis of interstitial lung disease and considerably reduced the indications for surgical biopsy.