A diagnosis of chronic obstructive pulmonary disease (COPD) is based on your signs and symptoms, history of exposure to lung irritants (such as smoking), and family history. Your doctor will need to do a complete physical examination. COPD symptoms can be slow to develop. Many of the symptoms are somewhat common. Your doctor will use a stethoscope to listen for abnormal breathing sounds and may order some or all of the following tests.
The most effective and common method for diagnosing COPD is spirometry. This easy, painless test measures lung function and capacity. The patient exhales as forcefully as possible into a tube connected to a small machine (spirometer). The results can be interpreted immediately. This test is most effective because it can determine COPD before significant symptoms appear. It can also help track the progression of COPD and monitor the effectiveness of treatment.
Blood tests can help determine if your symptoms are being caused by an infection.
An arterial blood gas test will measure the amount of oxygen in your blood. This is one indication of how well your lungs are working. This can help your doctor determine how severe your COPD is and whether you need oxygen therapy.
If you have symptomatic COPD and are less than 50 years old or if you are a nonsmoker with COPD, your doctor will probably check your levels of α1-antitrypsin, a protein that helps protect the lungs. This protein is produced by the liver and then released into the bloodstream. This test will help determine if there is a genetic cause for your illness. Another indication would be a family history of premature COPD.
A CT scan is a type of X-ray that creates a more detailed image than a standard X-ray. Whichever type your doctor chooses, an X-ray will give a picture of the structures inside your chest. These include your heart, lungs, and blood vessels. Your doctor will be able to see if you have evidence of COPD. If your symptoms are being caused by another condition such as heart failure, your doctor will be able identify that as well.
Your doctor may order a sputum examination, especially if you have a productive cough. Sputum is the mucus you cough up. Analyzing your sputum can help identify the cause of your breathing difficulties and may rule out some lung cancers. If you have a bacterial infection, it can be identified and treated.
Your doctor might request an ECG to determine if your shortness of breath is being caused by a heart condition.