American Board of Internal Medicine (ABIM) Certification Practice Exam

What FEV1/FVC ratio indicates the presence of COPD?

1. Greater than 75%

2. Between 70% and 75%

3. Less than or equal to 70%

4. Less than 80%

The correct answer is: Less than or equal to 70%

The presence of Chronic Obstructive Pulmonary Disease (COPD) is indicated by a reduced FEV1/FVC (Forced Expiratory Volume in 1 second/Forced Vital Capacity) ratio. Specifically, a ratio that is less than or equal to 70% is diagnostic of COPD. This threshold reflects significant airway obstruction and is a key criterion in the definition of the disease, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. In individuals with COPD, the airflow limitation is usually progressive and associated with an enhanced chronic inflammatory response in the airways and lung parenchyma to noxious particles or gases. The FEV1 denotes the volume of air exhaled in the first second of forced expiration, while FVC represents the total amount of air exhaled forcibly after the deepest inhalation. When the FEV1/FVC ratio falls below this critical value, it signifies that the individual has an obstructive defect typically seen in COPD. A ratio greater than 75% or even a range between 70% and 75% would typically suggest normal lung function or only mild obstructive changes, making these options inconsistent with the diagnosis of COPD. Therefore, confirmation of the diagnosis relies