All spirometry data are collected using the ndd EasyOne Spirometer (Zurich, Switzerland). Each spirometer is tested against the ATS 24 and 26 standard waveforms and certified that it meets the ATS requirements, and each system will be continuously standardized with a 3.0 liter syringe located at each site. Each clinical coordinator was certified by the PFT Core after spirometry training. The PFT data is uploaded daily to the PFT QA Center’s FTP site, and the PFT Core feeds the data directly into a quality assessment software package. Quality assessments are made on each study. Studies that fail the quality assessment are reviewed by the PFT QC committee to be deleted or accepted for the study data set.
