title: Instrument accuracy and reproducibility in measurements of pulmonary function.
abstract: BACKGROUND
  The objective of the study was to quantify the accuracy and reproducibility of five commercially available pulmonary function test (PFT) instruments (Collins CPL [Ferraris Respiratory; Louisville, CO]; Morgan Transflow Test PFT System [Morgan Scientific; Haverhill, MA]; SensorMedics Vmax 22D [VIASYS Healthcare; Yorba Linda, CA]; Jaeger USA Masterscreen Diffusion TP [VIASYS Healthcare]; and Medical Graphics Profiler DX System [Medical Graphics Corp; St. Paul, MN]) that are associated with spirometry and the measurement of pulmonary diffusing capacity.
  
  
  METHODS
  In a multifactor, single-center, repeated-measures, full factorial 90-day study, a pulmonary waveform generator and a single-breath simulator of diffusing capacity of the lung for carbon monoxide (Dlco) were used to perform simulations of FVC and Dlco maneuvers. Accuracy was assessed as the difference between the observed and simulated values. Reproducibility was determined as the coefficient of variation of all measurements made during the study.
  
  
  RESULTS
  All instruments demonstrated a high degree of accuracy in the measurement of FVC and FEV(1). Overall, the accuracies associated with the measurement of peak flow, forced expiratory flow, mid-expiratory phase, and diffusing capacity were generally lower and more variable among the instruments tested. The coefficients of variation of Dlco measurements over 90 days were higher than those observed for spirometry.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of assessing the accuracy and reproducibility of modern PFT instruments using simulation testing. Our results provide an assessment of the component of PFT accuracy and reproducibility that is due to instrumentation alone.
authors.affiliation: Pulmonary Laboratory, LDS Hospital and University of Utah, Eighth Ave and C St, Salt Lake City, UT 84143, USA. ldrjens1@ihc.com
authors.forename: Robert L
authors.initials: RL
authors.lastname: Jensen
authors.forename: John G
authors.initials: JG
authors.lastname: Teeter
authors.forename: Richard D
authors.initials: RD
authors.lastname: England
authors.forename: Heather J
authors.initials: HJ
authors.lastname: White
authors.forename: Eve H
authors.initials: EH
authors.lastname: Pickering
authors.forename: Robert O
authors.initials: RO
authors.lastname: Crapo
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D003198:Computer Simulation; D004867:Equipment Design; D005240:Feasibility Studies; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000502:physiology*; D011653:Pulmonary Diffusing Capacity / Q000295:instrumentation / Q000592:standards; D015203:Reproducibility of Results; D013147:Spirometry / Q000295:instrumentation / Q000592:standards; D014797:Vital Capacity / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide