What Is COPD?
Chronic obstructive pulmonary disease (COPD) is a serious condition that affects the lungs and makes breathing more difficult. The term COPD includes two conditions, emphysema and chronic bronchitis, which are specific types of lung problems that make it harder to breathe.
Most cases of COPD are caused by damage to the lungs from cigarette smoking. Exposure to other irritants, such as certain dusts or chemicals, can also contribute to the development of COPD.
People with COPD have difficulty with airflow, which means they struggle to exhale completely. As a result, air becomes trapped in the lungs. This makes it harder to breathe and interferes with the ability of the lungs to provide the body with the oxygen it needs.
COPD usually gets worse over time, frequently reducing a person’s quality of life and contributing to difficulty performing everyday activities. People with COPD often experience disease flare-ups, known as COPD exacerbations, that can significantly worsen symptoms. Overall, COPD is the fourth most common cause of death in the United States.
The Role of COPD Tests
Medical testing can play an important role in the detection and management of COPD. The purposes of COPD testing can depend on a patient’s situation and may include:
- Diagnosis: Tests of how well the lungs are working are central to diagnosing COPD in people with symptoms of the disease. Because many health problems can affect breathing and the lungs, careful testing helps differentiate COPD from other conditions. Accurately diagnosing COPD is important to help guide patient care, decrease symptoms, and improve quality of life.
- Determining COPD severity: Once COPD has been diagnosed, tests can be used to assess the severity of the condition and how much it is affecting lung function.
- Detection of coexisting conditions: Testing can help determine if a person has other medical conditions that can occur alongside COPD such as asthma, obstructive sleep apnea, lung cancer, or heart failure.
- Treatment planning: The way COPD is treated often depends on specific factors related to the patient’s health and the extent of the disease. Testing may be used to determine what kind of therapy is recommended and whether surgical treatments may be appropriate.
- Monitoring: COPD tests may be repeated periodically to see how the disease is progressing or to evaluate how well treatment is working.
- Assessment of flare-ups: When COPD exacerbations happen, tests can help determine the cause and severity of the flare-up.
For any specific patient, a doctor can explain which COPD tests are recommended and discuss the purpose of those tests.
Who should get testing?
COPD testing is typically performed in people who have symptoms that could be caused by the condition. Common symptoms of COPD include:
- Shortness of breath, especially with physical activity
- Regular cough
- Mucus production
- Chest tightness
Testing for COPD in people with these symptoms can help diagnose or rule out the presence of COPD. Early in the disease, COPD may cause few or mild symptoms, so doctors may recommend testing even if symptoms are not severe.
Diagnostic COPD testing is more common in people with symptoms who also smoke cigarettes or have exposures to other lung irritants. Doctors may use a questionnaire to identify patients at higher risk of COPD who are more likely to benefit from testing.
Testing for COPD is not recommended in people who do not have symptoms. This type of testing, known as screening, has not been shown to provide more benefits than downsides.
After COPD has been diagnosed, additional tests to assess disease severity, monitor disease progression, detect complications, or evaluate flare-ups are prescribed based on individual factors including a patient’s health history and overall health.
A doctor is in the best position to determine whether COPD testing is recommended for a specific person given the details of their situation.
Getting test results
The results of COPD testing are usually provided by your doctor or a lung specialist called a pulmonologist. Many tests of lung function provide nearly immediate results, but other COPD tests may require a few days for results to be available.
The doctor will typically evaluate your test results in the context of your health history and symptoms. If COPD is diagnosed, further tests may be recommended to determine its severity. The results of these tests may be discussed with you as they are performed, or your doctor may recommend several tests and then address how those tests are interpreted together.
Types of COPD Tests
There are multiple kinds of examinations and tests that can be involved in detecting and assessing COPD. The following sections provide more information about different types of COPD testing.
Most COPD testing starts with a physical examination. During the physical exam, the doctor may listen to your lungs with a stethoscope.
In addition to this exam, the doctor will do a health history review. This includes discussing your current symptoms including how serious they are and how long you have had them. The doctor will ask whether you smoke cigarettes or have other exposure to lung irritants. They may also ask about other conditions, such as asthma, that can affect your breathing.
Pulmonary function tests
Pulmonary function tests, also known as lung function tests, are a core part of COPD testing. These tests provide several ways of seeing how well you are breathing and whether your lungs are working normally.
Spirometry is the primary lung function test for COPD. During this test, you inhale deeply and then breathe out as hard as possible into a tube attached to a machine. The machine, known as a spirometer, measures both the amount of air you exhaled and how fast you breathed it out. In some cases, the doctor may give you medication with an inhaler and have you take the spirometry test again a few minutes later.
Lung volume tests measure the amount of air that your lungs can hold. The most common version, known as body plethysmography, involves sitting in a small room that looks like a phone booth. You then inhale and exhale through a mouthpiece, and the changes in the amount of air inside the booth reflect your lung volume.
Another type of lung volume test called a gas dilution test measures the amount of nitrogen or helium gas removed from a chamber after you have inhaled the gas through a connected tube.
Although often not needed to initially diagnose COPD, lung volume tests can provide more details about lung function that may be helpful for some patients.
Diffusing capacity tests assess how effectively your lungs are able to transfer oxygen from the air into your blood. To perform the test, you inhale a small amount of a harmless gas, hold your breath for a few seconds, and then exhale. The difference in the amount of gas that you breathed in and out is an indication of how well your lungs are absorbing oxygen into the bloodstream.
A diffusing capacity test is not routine and is most often used to gauge the extent of emphysema in smokers.
Pulse oximetry is a test that checks the oxygen levels in your blood, which is also called oxygen saturation. For this test, a small sensor is placed on your fingertip or earlobe. Pulse oximetry may be measured at multiple points and during various levels of physical activity. It can help determine the severity of COPD and whether supplemental oxygen therapy is necessary.
Arterial blood gas tests are another way to measure the amount of oxygen and carbon dioxide in the blood. These tests involve withdrawing blood from an artery and is typically taken from the wrist.
Fractional exhaled nitric oxide (FeNO) tests evaluate the amount of inflammation in the lungs. The test requires exhaling slowly and steadily into a tube. The air is transferred to a device that measures the level of nitric oxide, which is associated with inflammation. A FeNO test is most often used with asthma, which can occur alongside COPD, or as a way to further evaluate the symptoms of COPD.
Exercise tests are a way of seeing how your breathing, pulse, and oxygen levels change during physical activity. A common exercise test is the six-minute walk test, which involves walking indoors on a flat surface for six minutes. The distance you walk as well as your pulse and oxygen saturation are usually measured during the test.
Imaging tests may be used to examine the lungs and heart of people with COPD. The most frequent imaging tests are chest x-rays and chest CT scans.
These imaging tests are not necessary to diagnose COPD. They are most often used in specific scenarios when the causes of symptoms are unclear or when it is important to check for possible complications or coexisting conditions such as heart problems or pneumonia. They can also be used to see if a patient may benefit from surgery.
Another imaging test that may be prescribed is an echocardiogram, which provides an ultrasound picture of the heart. This test is mainly used to find out if heart problems are contributing to COPD symptoms. An electrocardiogram (ECG or EKG) that measures electrical activity of the heart can also be used for this purpose.
Laboratory blood tests are not essential to the diagnosis of COPD. However, they can provide important information about the cause of COPD. Blood tests can also help rule out other causes of breathing problems and detect health issues that can occur at the same time as COPD.
Arterial blood gas tests measure the amount of oxygen and carbon dioxide in the blood to help see how well your lungs are working.
Most people with COPD are tested for a deficiency of alpha-1 antitrypsin (AAT). AAT is a protein that helps maintain the health of the lungs and liver. A rare genetic defect causes AAT deficiency. AAT deficiency can result in COPD, including among nonsmokers. A blood test can determine whether AAT levels are normal or deficient.
Examples of additional blood tests that may be ordered by the doctor include:
- A complete blood count (CBC) or additional blood cell analysis to check for signs of anemia or other abnormalities in red and white blood cells that could affect a patient’s oxygen levels.
- Plasma brain natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP) tests, which can help identify heart failure that may be contributing to symptoms.
- A basic metabolic panel (BMP) or comprehensive metabolic panel (CMP) to determine whether there are signs of abnormal kidney function or an imbalance of electrolytes in the body. These tests can help identify a chronic increase in carbon dioxide in the blood and may also help differentiate COPD from other health conditions.
Tests for COPD Exacerbations
People who have COPD may experience periodic exacerbations when symptoms get worse than normal. These flare-ups may occur because of exposure to a specific trigger like a respiratory virus or bacteria.
When COPD exacerbations are mild, tests may involve only a physical exam and pulse oximetry to determine oxygen saturation.
If a COPD flare-up is more severe, further tests may be necessary. These can include arterial blood gas tests, blood tests to assess kidney and heart function, and imaging tests to look for signs of a lung infection.
Based on the situation, specific tests may also be used to try to identify the cause of the COPD exacerbation. For example, flu testing, COVID-19 testing, and/or testing for other respiratory viruses may be conducted to detect an active infection.
Getting Tested for COPD
Tests for COPD are usually ordered by a doctor after a patient has reported symptoms that could be related to COPD. Testing is normally performed in a medical office, hospital, or laboratory.
While a primary care physician is frequently involved in diagnosing COPD, other specialists may be involved in patient care. For example, a pulmonologist, respiratory therapist, and/or thoracic surgeon may be part of the healthcare team for a patient with COPD.
Although limited, some options exist for conducting certain types of COPD-related tests at home.
Most COPD testing is performed in a medical setting. Because there are many kinds of tests available, a doctor usually identifies the most appropriate test to conduct. Some COPD tests require specialized equipment that is not typically available with at-home testing.
Some types of lung function tests have been adapted for home testing. For example, patients who have been diagnosed with certain lung disorders are able to use a basic at-home spirometer to periodically monitor their breathing.
Some research has suggested that at-home spirometry can be effective for regular lung function testing in people with COPD. However, more research is needed to validate wider use of at-home testing and to optimize methods of enabling patients to take the test properly.
Because COPD is a serious medical condition, at-home testing should only be performed after first consulting with a doctor, and at-home tests should never be used in lieu of testing recommended by a physician.
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