The diagnosis of Chronic Obstructive Pulmonary Disease (COPD) involves a number of clinical evaluations, tests to measure your lung function, and imaging studies used to assess airflow and lung damage. Pulmonologists are able to determine your diagnosis by looking at your symptoms, including, but not limited to, a chronic cough or other respiratory symptoms and your smoking history. To determine how far along you are with your disease as well as how to treat your disease, you may undergo diagnostic tests. Such tests may be performed with a combination of spirometry, chest X-rays, CT Scans, blood testing and assessment of your oxygen level.