Chronic obstructive pulmonary disease (COPD) is often misdiagnosed or missed altogether. In the early stages of COPD, symptoms are mild and may be easily confused with other conditions.
Doctors diagnose COPD with a combination of detailed patient history, chest x-rays or CT scans, and a lung function test. The doctor may also take a blood sample to determine your blood oxygen level. Tests will determine whether the symptoms are caused by COPD or another health issue such as pneumonia, a bacterial infection, heart failure, or lung cancer. It is possible to have COPD and another heart or lung condition at the same time. During diagnosis, your doctor may or may not specify that you have a certain type of COPD.
COPD is most commonly diagnosed in people age 40 or older, and becomes more common with age.
How is COPD diagnosed?
Your doctor will take a thorough medical history and ask about symptoms you are experiencing. You will also be asked about family history of lung problems, whether you have ever smoked and are currently smoking, and any other health issues you may have, including asthma. The doctor will inquire about potential exposure to lung irritants such as smoke, chemicals, or toxins that may cause COPD.
Spirometry, the most common diagnostic tool when COPD is suspected, measures lung function. During a spirometry test, you breathe into a tube that evaluates lung function by monitoring how much air you are able to blow in one second. The doctor uses this measurement to calculate forced expiratory volume, or FEV1. Your FEV1 score helps determine whether you have COPD and, if so, what stage.
The doctor may also order additional tests to rule out other conditions or assess how far your COPD has progressed.
Chest X-rays and CT scans provide images of the heart, lungs, and blood vessels to determine any damage and signs of COPD versus another disease. X-rays can help identify whether or not you have emphysema. CT scans generally provide more detail than X-rays and can help rule out lung cancer.
An electrocardiogram or EKG assesses heart rhythm and can help determine whether shortness of breath is caused by problems in the heart or the lungs. EKG results can help rule out COPD. EKG tests, which are brief and painless, involve the placement of patches on the chest, arms, and legs. Wires connected to the patches send signals to a machine that records electrical activity as the heart beats.
Arterial blood gas (ABG)
Arterial blood gas or ABG helps assess lung function and lung disease progression. A blood sample is taken from an artery to measure blood oxygen and carbon dioxide levels. ABG results show how capable your lungs are at moving oxygen into your blood and eliminating carbon dioxide.
By analyzing the sputum (mucus), your doctor can determine whether breathing issues are caused by lung cancer or a bacterial infection rather than COPD.
A blood test for the genetic disorder alpha-1 antitrypsin deficiency (alpha-1) can help determine the cause of COPD, especially among non-smokers and people who develop COPD symptoms before age 40. People with alpha-1 produce a limited amount of a protein called alpha-1-antitrypsin (AAT), which helps protect the lungs. Alpha-1 can cause a form of emphysema, even without smoking. If you have alpha-1, your doctor may recommend treatments to increase the amount of AAT in your lungs.