Which of the following is the single most useful approach for diagnosing acute lung allograft rejection?

D. Fiberoptic bronchoscopy with transbronchial lung biopsy.

 DISCUSSION: Virtually all lung transplant patients experience at least one episode of acute rejection during their postoperative recovery in hospital. All of the approaches mentioned above are useful in leading to the diagnosis. Clinically, the patient experiences malaise and fever. There is also typically a slight decline in spirometry and arterial oxygenation. The chest radiograph typically shows a hilar or basal shadow; however, although these findings all suggest acute rejection, they are not specific. The one test with high specificity for detection of acute rejection is bronchoscopy with transbronchial lung biopsy.