[Pulmonary function testing: history up to the present]

The main roles of pulmonary function testing are: aiding in the diagnosis, assessing disease severity, and monitoring the progress and effects of treatment. The spirometric measurements of highest clinical value are the vital capacity(VC) and forced expiratory volume in one second(FEV1). Measurements of VC were reported in both healthy subjects and patients with respiratory disease during the mid-19th century. The VC, however, was little used in clinical medicine until the second half of the 20th century. The FEV1, FEV1/VC ratio, and/or FEV1/forced vital capacity (FVC) ratio all came into existence after 1950. Pulmonary function testing evolved over time into a more complex set of lung function measurements using various techniques and devices. If the variability of the results can be minimized and the measurement accuracy can be improved, abnormalities will be more easily detected. In 2005, the American Thoracic Society (ATS) and European Respiratory Society (ERS) together published an updated set of standards for pulmonary function testing that could be applied more widely. These standards are structured to cover definitions, equipment, and patient-related procedures commonly applied for many methods of lung function testing. In 2004, the Japanese Respiratory Society issued an initial set of recommendations for the standardized measurement of VC, FVC, and the single-breath carbon monoxide-diffusing capacity. These recommendations have not been updated, and the prediction equations for pulmonary function testing have not been fully established. The statements need to be periodically updated in accordance with new developments. (Review).