BAL is ideal for ______ airway dz.

• A. Focal
• B. Diffuse
• C. Diffuse focal
• D. Local

Answer: (B)

Bronchoalveolar lavage is most informative when the disease process involves many airways and alveoli, i.e., is diffuse. The lavage washes a portion of the lung and collects cells, proteins, and microbes from the alveolar spaces across a broad area, so the sample more accurately reflects the overall inflammatory or infectious pattern. This makes BAL especially useful for diagnosing diffuse interstitial or alveolar processes (such as certain infections, hypersensitivity pneumonitis, or sarcoidosis) where multiple regions are affected and the cellular profile guides interpretation. In contrast, if the disease is focal or localized, the abnormal tissue may lie outside the lavaged region, increasing the risk of a nondiagnostic result or missing the pathology. For focal disease, targeted sampling—like biopsy or brushing from the specific lesion—yields more reliable information.