To diagnose COPD, your doctor will probably do the following tests:

• Medical history and physical exam . These will give your doctor important information about your health.
• Lung function tests . These measure the amount of air in your lungs and the speed at which air moves in and out. Spirometry is the most important of these tests.
• Chest X-ray . This helps rule out other conditions with similar symptoms, such as lung cancer.

Tests done as needed

• Arterial blood gas test . This test measures how much oxygen, carbon dioxide, and acid is in your blood. It helps your doctor decide whether you need oxygen treatment.
• Oximetry . This test measures the oxygen saturation in the blood. It can be useful in finding out whether oxygen treatment is needed, but it provides less information than the arterial blood gas test.
• Electrocardiogram (ECG, EKG) or echocardiogram. These tests may find certain heart problems that can cause shortness of breath.
• Transfer factor for carbon monoxide . This test looks at whether your lungs have been damaged, and if so, how much damage there is and how bad your COPD might be.

Tests rarely done

• A test to measure levels of alpha-1 antitrypsin, or ATT. ATT is a protein your body makes that helps protect the lungs. People whose bodies don't make enough ATT are more likely to get emphysema.
• A CT scan. This gives doctors a detailed picture of the lungs.

Regular checkups

Because COPD is a disease that keeps getting worse, it is important to schedule regular checkups with your doctor. Checkups may include:

• Spirometry.
• Arterial blood gas test.
• X-rays or ECGs.

It's important to tell your doctor about any changes in your symptoms and whether you have had any flare-ups. Your doctor may change your medicines based on your symptoms.

Early detection

The sooner COPD is diagnosed, the sooner you can take steps to slow down the disease and maintain your quality of life for as long as possible. Screening tests help your doctor diagnose COPD early, before you have any symptoms.

Talk to your doctor about COPD screening if you:

• Are a smoker or ex-smoker.
• Have had asthma for a long time.
• Have a family history of emphysema.
• Have a job where you are exposed to a lot of chemicals or dust.