[Functional diagnosis of chronic obstructive pulmonary disease].

Functional diagnosis of chronic obstructive pulmonary disease is important for identifying and quantifying airflow limitation, reversibility, disease severity and exacerbations. Functional diagnosis is also important for long-term therapeutic monitoring and for establishing the need for pulmonary rehabilitation. From the functional standpoint, chronic obstructive pulmonary disease is characterised by a progressive airflow limitation which is not fully reversible. Spirometry is the gold standard for diagnosing the disease and monitoring its progression as it is non-invasive, standardised, reproducible, and objective. Spirometry should measure forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and the ratio of these two measurements. Post-bronchodilator FEV1 < 80% of the predicted value and FEV1/FVC ratio < 70% confirms the diagnosis of chronic obstructive pulmonary disease.