Standardization of spirometry and single breath DLCO tests.

Standards for patient care and especially for pulmonary function testing have become important world wide, especially in the United States [1, 2, 3]. Recently the American Thoracic Society (ATS) has published two new statements. One is an update of its spirometry standardization [1] and the other recommends standard techniques for the single breath diffusion capacity (transfer factor) or DLCo [2]. The 1987 ATS spirometry recommendation is an update from the 1979 document which had a great impact on the quality of equipment and testing in the United States. Standardization of spirometry tOOk on an international navour with the publication by the "Bulletin", in 1983, of the European Community for Coal and Steel recommendations on standardized lung function testing [41. The ATS originally established recommendations for spirometry as part of the "Epid~ miology Standardization Project" under the auspices of the Division on Lung Disease of the National Heart, Lung and Blood Institute [5]. Recently the A TS Board of Directors instructed their Committee on Proficiency Standards for Clinical Pulmonary Function Laboratories to update the recommendations on spirometry standardization. As briefly reported in the "Bulletin" [6] the same committee was also the convener of a conference in Alta, Utah, USA in October of 1984 to develop standard methods for Lhe single breath carbon monoxide diffusing capacity (Dt.co) (transfer factor or TL..Co). The All.a meeting was attended by international expcns with representatives from the USA and Europe (2]. Preliminary versions of the diffusing capacity document were circulated widely and reviewed by expert groups in the USA and Europe. Good inter-laboratory agreement has always been a goal of clinical pulmonary function testing laboratories. Strict standardization of equipment and of procedure is increasingly important as one step in improving inter-laboratory comparability. The need for standardization is greater the more complex the technique, as is the case with the DLCo measurement, since it involves measurement of volumes, time, and several gas concentrations (He, CO, 0 1 and COJ in the inhaled mhture and the sample of alveolar gas. Measurement of the forced vital capacity (FVC) manoeuvre with a spirometer has become a common