Basic pulmonary function tests available in the ambulatory setting include
Spirometry and pulse oximetry provide physiologic measures of pulmonary function and can be used to quickly narrow a differential diagnosis and suggest a subsequent strategy of additional testing or therapy. More complicated testing includes
Measurement of lung volumes
Lung, chest wall, and respiratory system compliance (which requires measurement of esophageal pressure)
Complete cardiopulmonary exercise testing
These tests provide a more detailed description of physiologic abnormalities and the likely underlying pathology. The choice and sequence of testing are guided by information taken from the history and physical examination.