Bronchoalveolar Lavage (BAL) is a medical procedure used to collect samples from the lungs. During this procedure, a thin tube called a bronchoscope is inserted into the airways. A sterile saline solution is then introduced and later suctioned back, capturing cells, fluid, and other substances from the lungs for analysis. BAL is often performed to diagnose lung diseases, infections, or conditions like pneumonia or pulmonary fibrosis. The samples obtained can help doctors identify pathogens, inflammatory cells, or cancerous cells, aiding in the development of appropriate treatment plans for patients.