[Problems of lung function testing in the laboratory].

Spirometry is indispensable for the screening test of general respiratory function, and measurements of lung volume and diffusing capacity play an important role in the assessment of disease severity, functional disability, disease activity and response to treatment. Pulmonary function testing requires cooperation between the subjects and the examiner, and the results obtained depend on technical as well as personal factors. In order to diminish the variability of results and improve measurement accuracy, the Japan Respiratory Society published the first guidelines on the standardization of spirometry and diffusing capacity for both technical and clinical staff in 2004. It is therefore essential to distribute the guidelines to both laboratory personnel and general physicians. Furthermore, training workshops are mandatory to improve their understanding of the basics of lung function testing. Recently, there has been increasing interest in noninvasive methods of lung function testing without requiring the patient's cooperation during spontaneous breathing. Three alternative techniques, i.e. the negative expiratory pressure (NEP) method to detect expiratory flow limitation, impulse oscillation system (IOS) to measure respiratory system resistance (Rrs) and reactance (Xrs), and interruption resistance (Rint) to measure respiratory resistance have been introduced. Further study is required to determine the advantage of these methods.