Page 38
Spirometry Tips -How To Do It and
Common Pitfalls and Problems
FEV1
°
As for FVC
°
Take largest FEV1 even if not from the same curve as the best FVC
°
Zero time determined by back-extrapolation - extrapolated volume
should be <5% of FVC or 0.15 liters, whichever is greatest
°
Smooth, rapid take off with no: hesitation, cough, leak, tongue
obstruction, glottic closure, Valsalva or early termination
°
Reproducibility: the highest and second highest FEV1 should agree
to within 0.2L
