We thank P. Degens and R. Merget for giving us the opportunity to comment on the reference equations suggested by the American Thoracic Society/European Respiratory Society Task Force on lung function testing 1.
We agree with P. Degens and R. Merget when they say that the European Community for Coal and Steel reference equations for lung function are too old to be used in modern medicine due to their limitations in predicting lung function in the general population. Recognising this as an unresolved issue …
