Your COPD guide to lung disease tests

To diagnose and manage COPD, your doctor may ask for a series of tests. There are many different tests that help your doctor gather information about your lungs and your breathing. A few screening tests are outlined below.

Before the tests, you will be told how to prepare for them. You may be told to wear loose clothing as well as to avoid large meals and stop using some of your medicines in the hours preceding the tests. 

Pulmonary function tests
These tests include spirometry, lung volume tests, and diffusing capacity tests. They measure how well the lungs are working and how well the lungs are moving oxygen to the blood. These breathing tests are done using special equipment by trained staff in a hospital or doctor’s office.  

Chest X-rays or CT scan
Both are X-rays. A chest X-ray is a photo taken while you sit or stand with your chest pressed to an X-ray machine. Unfortunately, this isn’t a good test for examining lung disease. A much better test is a computed tomogram, or CT, of the lungs. These tests are high-tech X-rays and are good for diagnosing two types of COPD: emphysema and bronchiectasis. 

Lab tests
Your doctor will use a couple of tests to decide if you need to be on oxygen. The first test measures arterial blood gases, and it can tell how well your lungs are getting oxygen into your blood and carbon dioxide out of your blood. It is the most accurate. 

The second test measures the amount of oxygen in the blood using a pulse oximeter, which is clipped to your finger or earlobe. It shines a special light through the skin to measure how much light is absorbed by hemoglobin in the blood. This test is not as accurate, so the arterial blood gases test is used more often in patients with severe COPD.  

Cardiopulmonary exercise testing
This exercise test is done on an exercise bike or a treadmill and helps your doctor determine how physically limited you are. In addition, your doctor can determine how much of your breathing problem is related to your heart, your lungs or your muscles. Often it may assist your doctor in setting up an exercise program specifically for your needs. 

Six-minute walk
This is a walking test. It measures how far you can walk in six minutes. It allows your doctor to determine your activity level and how much oxygen you may need.