If you have any of these symptoms, you are at risk for developing COPD.
Anyone with the following should get tested:
- Has a history of smoking
- Has long-term exposure to air pollutants (including pollution and second-hand smoke)1
- Has chronic coughing with or without sputum
- Has wheezing
- Has shortness of breath that has become worse over time
- Cannot keep up with people of your own age
Spirometry is a simple, non-invasive test that is used to diagnose COPD. When you take the test, you will be asked to blow all the air out of your lungs into a mouthpiece connected to a machine known as a spirometer.
The machine will calculate two numbers: the amount of air you blow out in the first second, and the amount of air you blow out in 6 seconds or more.
These numbers are represented as FEV1 and FVC (sometimes FEV6 is used). FEV1 stands for the Forced Expiratory Volume in the first second—the amount of air you exhaled in the first second of blowing. FVC stands for Forced Vital Capacity—the amount of air that you exhaled in one entire breath.
A spirometry test can also show your doctor how severe your COPD may or may not be. There are several stages of COPD2.
People with COPD have an FEV1/FEV6 (FVC) ratio less than 70%. The FEV1 percentage predicted indicates how severe the airways are obstructed (blocked or narrowed).
Less than 80% of predicted is considered moderate COPD, and less than 50% of predicted is severe. People with asthma will have a low FEV1/FEV6 ratio when they are having an attack, and then will return to normal or almost normal after using fast-acting medications.
Your doctor may order additional tests to see if your symptoms are caused by lung disorders other than COPD. One is Bronchodilator Reversibility Testing, which determines if your lung function improves significantly with medication.
Your doctor may also order a chest x-ray or a chest CT (high resolution computed tomography), which shows your lungs in much greater detail, to see if your symptoms are brought on by other problems instead of COPD.