▸Markers for acceptability of separate blows | | |
Flow–volume curve shows steep initial incline | Acceptable versus unacceptable | Yes |
Flow–volume curve shows sharp peak | Acceptable versus unacceptable | Yes |
Flow–volume curve shows uninterrupted forced expiration | Acceptable versus unacceptable | Yes |
Forced expiration of reasonable durationa | Acceptable versus unacceptable | Yes |
Forced expiratory time | <6 seconds versus ≥6 seconds | Yes |
Back-extrapolated volume | <5% of FVC or 0.15 litre, whichever is greater | No |
Volume–time curve shows an obvious plateaub | Acceptable versus unacceptable | No |
▸Markers for reproducibility of test | | |
Number of acceptable forced manoeuvres | ≥3 manoeuvres versus <3 manoeuvres | Yes |
Reproducibilityc of FEV1 | <0.2 litre versus ≥0.2 litre | Yes |
Reproducibilityc of FVC | <0.2 litre versus ≥0.2 litre | Yes |