Step 5: Determine Reversibility of the Obstructive Defect
If the patient has an obstructive defect, the physician should determine if it is reversible based on the increase in FEVor FVC after bronchodilator treatment (i.e., increase of more than 12% in patients five to 18 years of age, or more than 12% and more than 200 mL in adults). Figure 4 shows a fully reversible obstructive defect. Obstructive defects in persons with asthma are usually fully reversible, whereas defects in persons with COPD typically are not.