COPD airflow limitation severity criteria’s according to three recommendations
| Recommended tools | Severity categories | Post-BD FEV1/FVC (absolute) | Post-BD FEV1 |
| GOLD22 | Mild | <0.7 | ≥80% |
| Moderate | <0.7 | 50%–79% | |
| Severe | <0.7 | 30%–79% | |
| Very severe | <0.7 | <30% | |
| COPD-X23 24 | Mild | <0.7 | 60%–79% |
| Moderate | <0.7 | 40%–59% | |
| Severe | <0.7 | <40% | |
| GLI37 | Mild | ≤LLN | z-score ≥ −2 |
| Moderate | ≤LLN | −2.0>−3.0 | |
| Severe | ≤LLN | −3.0>−4.0 | |
| Very severe | ≤LLN | z-score≤−4.0 |
BD, bronchodilator; COPD, chronic obstructive pulmonary disease ; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; GLI, global lung function imitative; GOLD, global initiative for chronic obstructive lung disease; LLN, lower limit of normal.