Feigongneng Fev1 Fvc Fenji
Key formulas: fev1÷fev1pred×100; fvc÷fvcpred×100; ratio×100
| Item | Formula | Source-Standard |
|---|---|---|
| Airflow limitation | A post-bronchodilator FEV1/FVC below 0.70 defines persistent airflow limitation | Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of COPD, 2024 Report |
| Severity grading | Grades GOLD 1-4 are based on FEV1 as a percentage of the predicted value | Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of COPD, 2024 Report |
| Quality control | Acceptable expiratory time and repeatability are required for valid results | Graham BL et al. Am J Respir Crit Care Med 2019;200:e70-e88 (ATS/ERS spirometry standardization) |