GOLD COPD Staging (Grade 1-4)

Stage COPD severity by post-bronchodilator FEV1 % predicted. Grade 1 (Mild): FEV1 >= 80%; Grade 2 (Moderate): 50-79%; Grade 3 (Severe): 30-49%; Grade 4 (Very Severe): < 30%. Used with symptom burden (CAT/mMRC) for ABCD group classification.