Flexible bronchoscopy involves performing bronchoalveolar lavage, and this procedure is crucial because it provides detailed information about the immune, inflammatory, and infectious processes occurring at the alveolar level. It is extensively utilised to investigate and classify any lung disorders or infections that may be present at that time, as well as to examine the patients respiratory system in action. Despite the fact that there are other approaches available for dealing with these problems, the BAL method has gained popularity because of how effectively the test findings as a whole work.