Objective: To study the clinical, radiological, and histopathological patterns of transbronchial biopsy (TBB) used in order to confirm the diagnosis in patients with clinical suspicion of interstitial lung disease (ILD) treated at a tertiary-care university hospital. Methods: We reviewed the medical records, radiology reports, and reports of transbronchial biopsies from all patients with suspected ILD who underwent TBB between January of 1999 and December of 2006 at the Hospital das Clínicas de Botucatu, located in the city of Botucatu, Brazil. Results: The study included 56 patients. Of those, 11 (19.6%) had a definitive diagnosis of idiopathic pulmonary fibrosis (IPF), the rate of which was significantly higher in the patients in which ILD was a possible diagnosis in comparison with those in which ILD was the prime suspect (p = 0.011), demonstrating the contribution of TBB to the diagnostic confirmation of these diseases. The histopathological examination of the biopsies revealed that 27.3% of the patients with IPF showed a pattern of organizing pneumonia, which suggests greater disease severity. The most common histological pattern was the indeterminate pattern, reflecting the peripheral characteristic of IPF. However, the fibrosis pattern showed high specificity and high negative predictive value. For CT scan patterns suggestive of IPF, the ROC curve showed that the best relationship between sensitivity and specificity occurred when five radiological alterations were present. Honeycombing was found to be strongly suggestive of IPF (p = 0.01). Conclusions: For ILDs, chest CT should always be performed, and TBB should be used in specific situations, according to the suspicion and distribution of lesions.

Keywords: Lung diseases, interstitial; Diagnosis, differential; Bronchoscopy.