Pulmonary cytology

- tracheobronchial lavage, bronchoalveolar lavage can be used to recover mucus, cells and debris from the respiratory tract. Fluid is centrifuged, smeared onto a slide and examined. Components of normal washes:

• mucus. Inspissated mucus indicates poor ventilation of alveoli; granular mucus has been altered by neutrophil enzymes.
• epithelial cells. Some are present. Squamous epithelium coated with bacteria is from the oropharynx.
• leukocytes. Activated pulmonary alveolar macrophages are normal. More than 20% neutrophils is excessive. Eosinophils, lymphocytes and multinucleated giant cells indicate pathology.
• debris. Should be a small component. If excessive, may indicate aspiration pneumonia.