Bronchoalveolar lavage is a procedure where samples of fluid, secretions and cells are obtained from deep within the respiratory tract. First a bronchoscopy is performed. Then, several doses of sterile saline are infused into the deep airways through the endoscope and then immediately suctioned out of the airways and saved for analysis. Within this fluid, cells, mucus and microorganisms that were in the airways may be present. The samples are analyzed for inflammation, infection or cancer by a veterinary pathologist. The samples can also be cultured to identify a variety of microorganisms including bacteria and fungus.