Table. 6—

Range and accuracy recommendations specified for forced expiratory manoeuvres

TestRange/accuracy (BTPS)Flow range L·s−1Time sResistance and back pressureTest signal
VC0.5–8 L, ±3% of reading or ±0.050 L, whichever is greater0–14303-L Calibration syringe
FVC0.5–8 L, ±3% of reading or ±0.050 L, whichever is greater0–1415<1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1)24 ATS waveforms, 3-L Cal Syringe
FEV10.5–8 L, ±3% of reading or ±0.050 L, whichever is greater0–141<1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1)24 ATS waveforms
Time zeroThe time point from which all FEVt measurements are takenBack extrapolation
PEFAccuracy: ±10% of reading or ±0.30 L·s−1 (20 L·min−1), whichever is greater; repeatability: ±5% of reading or ±0.15 L·s−1 (10 L·min−1), whichever is greater0–14Mean resistance at 200, 400, 600 L·min−1 (3.3, 6.7, 10 L·s−1) must be <2.5 cmH2O·L−1·s−1 (0.25 kPa·L−1·s−1)26 ATS flow waveforms
Instantaneous flows (except PEF)Accuracy: ±5% of reading or ±0.200 L·s−1, whichever is greater0–14<1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1)Data from manufacturers
FEF25–75%7.0 L·s−1, ±5% of reading or ±0.200 L·s−1, whichever is greater±1415Same as FEV124 ATS waveforms
MVV250 L·min−1 at VT of 2 L within ±10% of reading or ±15 L·min−1, whichever is greater±14 (±3%)12–15<1.5 cmH2O·L−1·s−1 (0.15 kPa·L−1·s−1)Sine wave pump
  • BTPS: body temperature and ambient pressure saturated with water vapour; VC: vital capacity; FVC: forced vital capacity; ATS: American Thoracic Society; FEV1: forced expiratory volume in one second; FEVt: forced expiratory volume in t seconds; PEF: peak expiratory flow; FEF25–75%: mean forced expiratory flow between 25% and 75% of FVC; MVV: maximum voluntary ventilation; VT: tidal volume.