Diagnosis
COPD is commonly misdiagnosed. Many people who have COPD may not be diagnosed until the disease is advanced.
To diagnose your condition, your doctor will review your signs and symptoms, discuss your family and medical history, and discuss any exposure you've had to lung irritants — especially cigarette smoke. Your doctor may order several tests to diagnose your condition.
Tests may include:
Lung (pulmonary) function tests. These tests measure the amount of air you can inhale and exhale, and whether your lungs deliver enough oxygen to your blood. During the most common test, called spirometry, you blow into a large tube connected to a small machine to measure how much air your lungs can hold and how fast you can blow the air out of your lungs. Other tests include measurement of lung volumes and diffusing capacity, six-minute walk test, and pulse oximetry.
Chest X-ray. A chest X-ray can show emphysema, one of the main causes of COPD. An X-ray can also rule out other lung problems or heart failure.
CT scan. A CT scan of your lungs can help detect emphysema and help determine if you might benefit from surgery for COPD. CT scans can also be used to screen for lung cancer.
Arterial blood gas analysis. This blood test measures how well your lungs are bringing oxygen into your blood and removing carbon dioxide.
Laboratory tests. Lab tests aren't used to diagnose COPD, but they may be used to determine the cause of your symptoms or rule out other conditions. For example, lab tests may be used to determine if you have the genetic disorder alpha-1-antitrypsin deficiency, which may be the cause of COPD in some people. This test may be done if you have a family history of COPD and develop COPD at a young age.
