Safety of the transbronchial biopsy in outpatients. The objective of our study was to determine the safety of transbronchial biopsy (TBB) in nonhospitalized patients. The design was a prospective study of the consecutive cases from July 1987 until September 1988 in the setting of a university hospital of the third level with 1,800 beds. The patients were a consecutive sample of 169 patients who had 184 procedures of fiberoptic bronchoscopy (FOB) with TBB performed. They suffered from different diseases: lung nodules or masses, diffuse interstitial disease, alveolar condensation, etc. An FOB with TBB was performed in immunocompetent outpatients, who were kept under observation for four hours and then had a chest roentgenogram taken afterwards. We contacted them again after 72 hours to rule out delayed complications. In three cases, more than 100 ml of blood were obtained during the FOB, without significant hemoptysis being recorded in those patients during the observation period; chest pain occurred in 15 patients during the TBB; pneumothorax occurred in two patients (1 percent), one of whom required admission to the hospital, without requiring chest tube drainage. Other complications are reported (bronchospasm, parenchymal hemorrhage, and pneumonia). In conclusion, we consider the TBB to be a technique with a low incidence of complications for outpatients, so therefore we do not believe that admission to the hospital is mandatory for this type of patient, although we do recommend a longer observation period. 