“To diagnose chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema, your doctor will evaluate your symptoms, ask for your complete health history, conduct a health exam and examine test results.  The pt is tested through spirometry. Spirometry is a simple test of how well your lungs work. For this test, you blow air into a mouthpiece and tubing attached to a small machine. The machine measures the amount of air you blow out and how fast you can blow it.   Also a chest X-ray and/or other tests, such as an arterial blood gas test, which measures the oxygen level in your blood. When you are diagnosed with chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema, you likely will have many questions and the answers may not always be clear at first. Not all people with COPD have the same symptoms and treatment may differ from person to person. It is important to talk to your doctor about your treatment options and to get answers to all of your questions.”

American Lung Association (https://www.lung.org/lung-health-diseases/lung-disease-lookup/copd/treating)