COPD is a group of lung diseases that block airflow and make it difficult to breathe. Emphysema and Chronic bronchitis are the most common conditions that make up COPD.
COPD compromises lung capacity as well as lung function and it is diagnosed by doing lung function tests. Spirometry is the most common lung function test. It measures how much and how quickly you can move air out of your lungs with the help of a machine called a Spirometer.