LUNOKID: can numerical American Thoracic Society/European Respiratory Society quality criteria replace visual inspection of spirometry?

Eur Respir J. 2014 May;43(5):1347-56. doi: 10.1183/09031936.00058813. Epub 2013 Nov 14.


The gold standard for assessing quality of forced expiratory manoeuvres is visual inspection by an expert. American Thoracic Society/European Respiratory Society numerical quality criteria (NQC) include back-extrapolated volume (BEV), repeatability and forced expiratory time (FET). Equipment currently available provides feedback tempting the investigator to use NQC as pass-fail criterion. To investigate whether using NQC instead of visual acceptability is a valid option, we analysed data from a multicentre national reference study in Germany of children aged 4-18 years. Spirometry was performed under field conditions. Receiver operating characteristic analysis was used to assess performance of BEV, repeatability, FET and a combination thereof in relation to visual acceptability. We included data from 3133 healthy Caucasians in the analyses; 72% delivered at least two visually acceptable manoeuvres. Of these, 59% would have been rejected based on combined NQC, mainly because the FET criterion was not feasible. Specificity of the NQC was generally low (BEV 10%, repeatability 30% and FET 50%). Receiver operating characteristic analysis showed that a combination of the three measures could reach at best a sensitivity of 90% and specificity of 56%. We conclude that visual control is mandatory and NQC may help obtain the best possible results, but a fixed cut-off for FET should be abandoned.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Algorithms
  • Child
  • Child, Preschool
  • Diagnosis, Computer-Assisted
  • Exhalation
  • Female
  • Forced Expiratory Volume
  • Germany
  • Humans
  • Male
  • Models, Theoretical
  • Observer Variation
  • Pulmonary Medicine / organization & administration*
  • Pulmonary Medicine / standards*
  • ROC Curve
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Software
  • Spirometry / methods*
  • Surveys and Questionnaires
  • United States
  • Vital Capacity