Summary of criteria
 Expiratory
airway obstruction |
FEV1%(F)VC (corrected for age and gender) |
| No obstruction |
above 5th percentile, and no bronchodilator
response |
| Mild obstruction |
below 5th percentile and FEV1%pred >60% ,
or
above 5th percentile and bronchodilator response |
| Moderate obstruction |
below 5th percentile and FEV1%pred 40-59% |
| Severe obstruction |
below 5th percentile and FEV1%pred <40% |
| Bronchodilator
response |
Criteria for grading of response |
| No response |
Increase in FEV1 <
200 mL and < 9% initial FEV1 |
| Mild response |
Increase in FEV1 >
200 mL and/or > 9% initial FEV1 |
| Marked response |
Increase in FEV1 >
12% initial FEV1 and > 200 mL |
| Possibly response |
According to FEV1 no bronchodilator responsiveness, but increase in (F)VC
> 340 mL and/or > 12% initial value and fall in
FEV1%(F)VC <
2%: the increase in (F)VC might reflect better subject
cooperation |
| Reversibility of airway obstruction |
|
| No reversibility |
Airway obstruction but no response to bronchilator
drug |
| Partial reversibility |
In spite of the response to a bronchodilator
drug the FEV1%(F)VC
is still below the 5th percentile |
| Completely reversible |
FEV1%(F)VC
after the bronchodilator drug is above the 5th percentile |
| VC
too low |
Criterion |
| Moderate |
below 5th percentile but SDS* > -3 |
| Severe |
SDS* < -3.0 |
| FEV1 |
Criterion |
| Too low |
below 5th percentile |
* standard deviation score = Z-score