How Is COPD Diagnosed?
Doctors consider a diagnosis of chronic obstructive pulmonary disease (COPD) if you have the typical symptoms and a history of exposure to lung irritants, especially cigarette smoking. A medical history, physical exam, and breathing tests are the most important tests to determine if you have COPD.
Your doctor will examine you and listen to your lungs. Your doctor will also ask you questions about your family and medical history and what lung irritants you may have been around for long periods of time.
Your doctor will use a breathing test called spirometry (speh-ROM-eh-tree) to confirm a diagnosis of COPD. This test is easy and painless and shows how well your lungs work. You breathe hard into a large hose connected to a machine called a spirometer (speh-ROM-et-er). When you breathe out, the spirometer measures how much air your lungs can hold and how fast you can blow air out of your lungs after taking a deep breath.
Spirometry is the most sensitive and commonly used test of lung functions. It can detect COPD long before you have significant symptoms.
Based on this test, your doctor can determine if you have COPD and how severe it is. Doctors classify the severity of COPD as:
- At risk (for developing COPD). Breathing test is normal. Mild signs that include a chronic cough and sputum production.
- Mild COPD. Breathing test shows mild airflow limitation. Signs may include a chronic cough and sputum production. At this stage, you may not be aware that airflow in your lungs is reduced.
- Moderate COPD. Breathing test shows a worsening airflow limitation. Usually the signs have increased. Shortness of breath usually develops when working hard, walking fast, or doing other brisk activities. At this stage, a person usually seeks medical attention.
- Severe COPD. Breathing test shows severe airflow limitation. A person is short of breath after just a little activity. In very severe COPD, complications like respiratory failure or signs of heart failure may develop. At this stage, the quality of life is greatly impaired and the worsening symptoms may be life threatening.
Your doctor may also recommend tests to rule out other causes of your signs and symptoms. These tests include:
- Bronchodilator (brong-ko-di-LA-tor) reversibility testing. This test uses the spirometer and medicines called bronchodilators. Bronchodilators work by relaxing tightened muscles around the airways and opening up airways quickly to ease breathing. Your doctor will use the results of this test to see if your lung problems are being caused by another lung condition such as asthma. However, since airways in COPD may also be constricted, your doctor can use the results of this test to help set your treatment goals.
- Other pulmonary function testing. For instance, your doctor could test diffusion capacity.
- A chest x ray is a picture of your lungs. A chest x ray may be done to see if another disease, like heart failure, may be causing your symptoms.
- Arterial blood gas. This is a blood test that shows the oxygen level in your blood. It is measured in people with severe COPD to see if oxygen treatment is recommended.