When you are first talking to your clinician about the possibility of having COPD, they may order various tests to figure out what is going on. Let’s cover the basics of COPD diagnostic tests. The main diagnostic test for COPD is called spirometry. In a spirometry test, you blow through a tube as hard, and as fast as you can to measure the amount of air your lungs move. The computer will measure the amount of air you blow out in the first second of your exhale (called the forced expiratory volume in 1 second, or FEV1) and the entire amount of air you blow out (called the forced vital capacity, or FVC), and compare them to each other. Most diagnostic guidelines state that you have COPD if your FEV1 is less than 70% of your FVC. Spirometry can help clinicians figure out whether your shortness of breath is from COPD or something else.
When I worked in primary care, I had several patients who were told they had COPD for many years, but when we did a spirometry test, we found they had other conditions that looked like COPD (things like asthma or vocal cord problems) but were not COPD. Once we could give them the right diagnosis, we got them on the right treatments. We also had lots of people that we put on COPD management plans once we had a correct diagnosis.
Once diagnosed with COPD, you may want to consider other COPD diagnostic tests, including getting tested for alpha-1 antitrypsin deficiency (AATD). Alpha-1 is sometimes called genetic COPD because it is inherited from your parents rather than being caused by childhood illness, smoke, or other pollutants, other means of getting COPD. With this condition, your body does not create enough of a certain enzyme, which can cause damage to your lungs and liver. A special kind of therapy called augmentation therapy can help bring your enzyme levels back to normal, which often slows down that damage. Unfortunately, only about one in 10 people with alpha-1 have been diagnosed. Blood tests can check for alpha-1, but your provider's office may also use free cheek swab tests. That way, you can be sure you are getting all the therapies that can help.
People with COPD also get their oxygen levels checked regularly. The most common way to do this is with a pulse oximeter. Pulse oximeters shine a light through your finger to measure how many red blood cells carry oxygen. You may already have a pulse oximeter at home. If not, it’s good to have a quality one on hand to check your oxygen levels. If they get too low, you may need supplemental oxygen therapy to prevent your organs from being damaged. Another way to measure your oxygen is called an arterial blood gas (ABG) test. Blood is drawn from an artery in your wrist and analyzed in a special machine. This way is more accurate than pulse oximetry, but many people like to avoid needles when they can.
Finally, new methods to diagnose COPD include things like CT scans. These are very high-resolution X-ray scans where you lay on a flat table and slide through a ring-shaped machine that scans the inside of your body. CT scans are maybe best known for finding lung cancer. The United States Preventative Services Task Force recommends that most people with a 20-pack-year or more smoking history (which includes a lot of people with COPD) get a screening CT scan for lung cancer every year. CT scans can also find damage from things like emphysema and bronchiectasis, which makes it even more important to have them done.
We know that many people with COPD get diagnosed later in life after a lot of lung damage has been done. That could be because the symptoms of COPD are often vague: coughing, getting tired more easily, that sort of thing. People also start taking the elevator instead of the stairs because they may think they are just getting older or they are a little out of shape. Many people do not realize the problems COPD is causing inside their lungs until they end up with their first exacerbation (symptom flare-up). However, the earlier clinicians diagnose COPD, the more we can do to slow down its progress and improve someone’s quality of life. That is why it is so important to pay attention to the messages your body sends and to stay in close contact with your clinical team. The earlier you get diagnosed correctly, the better!
Now I would like to hear from you! What tests did you have when you were first diagnosed? Are there other tests we should talk about? Let me know in the comments!