The role of pulmonary function testing in pulmonary fibrosis.

Interstitial lung diseases are characterized by disruption of the distal pulmonary parenchyma. The clinical history manifestations, cough and dyspnea, and physical exam manifestations, inspiratory crackles, are nonspecific. Pulmonary function testing aids in the evaluation and management of patients with interstitial lung disease although the pattern of abnormality is nonspecific. Pulmonary function testing can provide an estimate of histologic severity but not a definitive quantification of histologic fibrosis or inflammation. Pulmonary function tests can provide a baseline estimation of prognosis and be used to monitor disease progression or response to therapy. The forced vital capacity and diffusion capacity are the most valuable serial measurements, but further data are required to examine composite scoring and exercise gas exchange.