In many cases, patients experiencing symptoms of chronic obstructive pulmonary disease (COPD), such as coughing or wheezing, have already been diagnosed with either chronic bronchitis or emphysema. In some instances, patients will be diagnosed with one of these two conditions and COPD at the same time. People experiencing symptoms of COPD should immediately notify their physician.

Diagnosis of COPD typically begins with a complete medical history and physical examination. In addition to asking about the symptoms of COPD, the physician will listen to the patient’s chest. If the patient has already been diagnosed with emphysema, the physician will listen for a hollow noise from the chest. If the patient has already been diagnosed with bronchitis, the physician will listen for a wheezing noise from the chest. Additional symptoms may include hyperinflation of the chest.

As part of diagnosing COPD, the physician may also perform any of the following tests:

• Arterial blood gas analysis. In this test, blood is drawn from the patient’s artery to measure the levels of oxygen and carbon dioxide. Low oxygen (hypoxia) and high carbon dioxide (hypercapnia) may indicate chronic bronchitis.
  
  
• Chest x-ray. Although early signs of COPD will not be seen on a chest x-ray, chronic bronchitis might be indicated by the presence of scarring and enlarged walls of the airways. This is called a “dirty chest.” Also, the chest x-rays of advanced emphysema patients often reveal a constricted diaphragm, overly inflated lungs, large spaces (bullae) in the lungs and an abnormally small heart. A type of chest x-ray called a computed axial tomography (CAT) scan may also be done.
  
  
• Exercise stress test. This test identifies the level at which a patient is able to exercise safely. Oxygen may be administered during the test if needed.
  
  
• Spirometry. The patient forcefully exhales into a special device (a spirometer) that tells the physician how fully the lungs can inflate, and how severely the airways are obstructed. The patient’s ability to breathe is called the forced expiratory volume (FEV1). Although FEV1 normally begins to deteriorate slowly around the age of 20, people who smoke will have an FEV1 that deteriorates 2 to 3 times faster than normal. Thus, someone with COPD might begin to experience shortness of breath about 20 years sooner than someone without the disease. This test is often used to monitor COPD and the effectiveness of therapy.
  
  
• Pulse oximetry (“pulse ox”). This quick, painless test measures the amount of oxygen in the blood by attaching a small probe to the ear or finger.
  
  
• Sputum analysis. A sample of the patient’s mucus is taken for analysis to see if there is a respiratory infection.