Bronchoalveolar lavage is a diagnostic procedure used to collect fluid and cells from the lower airways (bronchi and alveoli). It involves passing a sterile fluid into the lungs through a flexible tube inserted into t he airways via endoscopy. The fluid is then withdrawn and analyzed to diagnose respiratory diseases such as pneumonia, inflammatory airway disease, and equine asthma. BAL is particularly useful for diagnosing conditions such as inflammatory airway disease (IAD), recurrent airway obstruction (RAO), and other lower respiratory tract infections.