transbronchial biopsy

Transbronchial biopsy is a way to grab a tiny piece of lung tissue from the inside, without cutting through the chest wall. During bronchoscopy, small forceps are passed down the scope's working channel into a far airway and nudged through its thin wall to pinch out a sample of the surrounding lung. The route is “across the bronchus” — trans-bronchial — which is where the name comes from.

It is used when looking and washing are not enough and actual lung tissue is needed under the microscope — to diagnose certain interstitial lung diseases, sarcoidosis, infections, rejection after lung transplant, or to reach a peripheral nodule. Because the airway lining has no pain fibres, the patient does not feel the pinch, and the procedure is added on during a standard flexible bronchoscopy.

The samples are small, which is its main limitation: a tiny fragment may miss patchy disease or be too little to classify a complex condition, so a non-diagnostic result does not exclude disease and a larger surgical biopsy is sometimes still required. The two notable risks are bleeding and pneumothorax, since the forceps work close to blood vessels and the lung's outer surface; a chest X-ray is often checked afterwards. A newer variant uses a freezing probe (cryobiopsy) to retrieve larger, better-preserved pieces.