If you go to the doctor with shortness of breath, a persistent cough, and excess phlegm production, they're likely to suspect chronic obstructive pulmonary disease — especially if you're a smoker or have been exposed to irritants at work. To rule out other conditions and ultimately confirm a diagnosis of COPD, however, you can expect a lot of tests. What are they, and what should you know about them?
A spirometry, also called a pulmonary function test, is the simplest and most effective way to diagnose COPD. During a spirometry, you'll be asked to breathe into a tube connected to the actual spirometer as forcefully as you can. From there on, your doctor will be able to tell your forced vital capacity (FVC), or the air volume you're able to expel in one total breath. They'll also look at what percentage of this total was expelled in the first second of the breath. This important figure is called your FEV1, or forced expiratory volume.
A bronchodilator spirometry is a test in which you'll be given a medication to relax and widen your airways, and it can not only diagnose COPD, but also tell what stage you're in:
- Mild COPD (Stage 1) patients will have an FEV1 of around 80 percent
- Moderate COPD (Stage 2) patients will have an FEV1 of between 50 and 80 percent
- Severe (Stage 3) patients can expect to have an FEV1 of between 30 and 50 percent
- Very severe (end-stage or Stage 4) patients will generally have an FEV1 of less than 30 percent
2. Bronchodilator reversibility test
A bronchodilator reversibility test can be used to determine how well patients already diagnosed with COPD or asthma are responding to bronchodilator therapy. This uses a spirometer, too. The initial step involves a spirometry without a bronchodilator, to establish how your lungs are working on their own. Fifteen minutes later, a bronchodilator is added. The results will tell your doctor if your treatment is right for you, or needs to be altered.
3. Arterial blood gas test
This tests serves to determine your blood levels of both oxygen and carbon dioxide, giving your doctor valuable insights into your lung function. An arterial blood gas test helps determine what stage of COPD you are currently in and can tell your doctor whether you may benefit from supplemental oxygen treatment.
4. Genetic testing
Patients with a deficiency of alpha-1 antitrypsin, a protein that helps guard your lungs against inflammation from pollutants they're exposed to, have higher odds of developing chronic obstructive pulmonary disease, and at younger ages, too. This is a genetic issue, and your doctor can check if you have it with a blood test.
5. A chest x-Ray
A chest x-ray can also be part of the COPD diagnostic process, as it allows your doctor to get a look at the physical state of your lungs. It can sometimes show whether you may have a respiratory infection or lung cancer, and and reveal emphysema, one of the conditions that fall under the COPD umbrella. Your doctor will be looking out for bullae (enlarged air sacs), enlarged lungs, and a flattened diaphragm, features that can show up in the more severe stages of COPD.
6. A chest CT scan
A CT scan can show more than a chest x-ray, and can also be employed during the diagnostic process for COPD as well as to determine whether an already diagnosed patient has suffered disease progression. A CT scan can help rule other conditions, sucg as lung cancer, in or out and clearly shows emphysema in its earlier stages.
7. A sputum examination
A sputum (or phlegm, or mucus) biopsy can help determine why you are short of breath and can diagnose bacterial infections. Having a bacterial infection doesn't mean you do not also suffer from COPD, and research revealed that positive results generally indicate poorer health and a higher risk of depression. Timely diagnosis, as always, facilitates timely treatment — so a sputum biopsy can be very helpful, even if patients find coughing up enough phlegm for the test to be a hard task.
8. What other tests may your doctor order while diagnosing COPD?
Other tests can be used to:
- Confirm the diagnosis of COPD
- Determine how severe your COPD is
- Rule heart disease and asthma in or out
These tests often include an electrocardiogram (ECG), which measures the electrical activity of the heart, and an ultrasound of your heart (echocardiogram). A so-called peak flow test, on the other hand, looks at the maximum speed with which you can expel air as you exhale. This is useful when differentiating between COPD and asthma.