TABLE 1

Computer algorithms for assigning quality criteria grades for forced vital capacity (FVC)

GradeAcceptable blows nRepeatableEOT criteria met#,¶?
A≥3≤150 mLYes
B2≤150 mLYes
C≥2≤200 mLYes
D≥2≤250 mLYes
F1NAYes
  • EOT: end-of-test; NA: not applicable. #: FVC only; : during the original analysis of the National Health and Nutrition Examination Survey dataset, EOT was defined according to the 1987 American Thoracic Society (ATS) recommendations as no change in volume (i.e. <40 mL over 2 s) or exhalation for >15 s [2]. In the current review, analysis was repeated after amending this to the 1994 ATS recommendations (i.e. <25 mL for ≥1 s [3] and, in subjects aged >10 years, exhalation for >6 s [1]).