A diagnosis of chronic obstructive pulmonary disease (COPD) is based on your signs and symptoms, history of exposure to lung irritants (such as smoking), and family history. Your doctor will need to do a complete physical examination before determining a diagnosis.
COPD symptoms can be slow to develop, and many of its symptoms are somewhat common. Your doctor will use a stethoscope to listen to both heart and lung sounds and may order some or all of the following tests.
The most effective and common method for diagnosing COPD is spirometry, also known as a pulmonary function test or PFT. This easy, painless test measures lung function and capacity.
To perform this test, you will exhale as forcefully as possible into a tube connected to the spirometer, a small machine. The total volume of air exhaled from your lungs is called the forced vital capacity (FVC). The percentage of the FVC forced out in the first second is called the FEV1. FEV stands for forced expiratory volume. The maximum speed at which you empty your lungs is called the peak expiratory flow rate (PEFR).
Spirometry results help determine which type of lung disease you have and its severity. The results can be interpreted immediately. This test is the most effective because it can determine COPD before significant symptoms appear. It can also help your doctor track the progression of COPD and monitor the effectiveness of treatment.
Because spirometry requires you to exhale forcefully, it’s not recommended for someone who has recently had a heart attack or heart surgery. It’s important to be fully recovered from any serious illnesses or conditions prior to testing. Even if you’re in basically good health, you may feel a little breathless and dizzy immediately after the test.
Bronchodilator reversibility test
This test combines spirometry with the use of a bronchodilator, which is medicine to help open up your airways.
For this test, you’ll undergo a standard spirometry test to get a baseline measurement of how well your lungs are working. Then, after about 15 minutes, you’ll take a dose of bronchodilator medication and repeat the spirometry test.
This screening is helpful in determining whether your current bronchodilator therapy is working or if it needs to be adjusted.
Blood tests can help your doctor determine whether your symptoms are being caused by an infection or some other medical condition.
An arterial blood gas test will measure the levels of oxygen and carbon dioxide in your blood. This is one indication of how well your lungs are working. This measurement can indicate how severe your COPD is and whether you may need oxygen therapy.
Most people have no problems with blood tests. There may be some discomfort or very minor bruising where the needle is inserted, but those side effects don’t last long.
If you have symptomatic COPD and are younger than 50 years old or if you’re a nonsmoker with COPD, your doctor may check your levels of alpha-1 antitrypsin (AAT). This protein, which helps protect your lungs, is produced by your liver and then released into your bloodstream. People with low levels of this protein have a condition called alpha-1 antitrypsin deficiency and often develop COPD at a young age.
While smoking and exposure to harmful substances in the environment are the main causes of COPD, there’s also a hereditary risk factor for this condition. A family history of premature COPD may signal that you have the condition. Through genetic testing, you can find out if you have an AAT deficiency.
AAT helps protect your lungs from inflammation caused by irritants such as pollution or smoking. If you have COPD but you’ve never smoked or worked around harmful chemicals and pollutants, you may be AAT deficient.
Genetic testing for AAT deficiency is done with a blood test. The blood test is usually harmless. But finding out you’re AAT deficient may be challenging, especially if you haven’t been diagnosed with COPD. Being AAT deficient doesn’t guarantee you’ll eventually have lung problems, but it does increase the odds.
X-ray or CT scan
A CT scan is a type of X-ray that creates a more detailed image than a standard X-ray. Any type of X-ray that your doctor chooses will give a picture of the structures inside your chest, including your heart, lungs, and blood vessels. Your doctor will be able to see if you have evidence of COPD. If your symptoms are being caused by another condition such as heart failure, your doctor will be able to identify that as well.
CT scans and standard X-rays are painless, but they do expose you to small amounts of radiation. The radiation used for a CT scan is greater than that required for a typical X-ray. While the doses of radiation for each test are relatively low, they do contribute to the amount of radiation exposure you receive over your lifetime. This can slightly raise your risk of cancer. However, new CT equipment requires less radiation to produce detailed images than previous technology.
Your doctor may order a sputum examination, especially if you have a productive cough. Sputum is the mucus you cough up.
Analyzing your sputum can help identify the cause of your breathing difficulties and may help detect some lung cancers. If you have a bacterial infection, it can also be identified and treated.
Coughing enough to produce a sputum sample may be uncomfortable for a few moments. Otherwise, there are no real risks or downsides to a sputum examination. It can be very helpful in diagnosing your condition.
Your doctor might request an EKG, or electrocardiogram, to determine if your shortness of breath is being caused by a heart condition as opposed to a lung problem. Over time, though, the breathing difficulties associated with COPD can lead to cardiac complications including abnormal heart rhythms, heart failure, and heart attack. An EKG measures the electrical activity in your heart, and can help diagnose a disturbance in your heart rhythm.
The EKG is generally a safe test with few risks. Sometimes you may experience a little skin irritation in the area where an electrode is placed. If an EKG involves an exercise stress test, the screening may help uncover any abnormal heart rhythms.
Preparing for COPD testing
COPD tests require little preparation. You should wear comfortable clothes and avoid big meals beforehand. You should also arrive at your appointment early to fill out any necessary paperwork.
Prior to spirometry or EKG tests, check in with your doctor about any medications. Certain drugs, caffeine, smoking, and exercise may affect your test results. For example, if you’re having a bronchodilator reversibility test, you may need to hold off on using your bronchodilator until that portion of the test.
Check with your doctor or the testing center a few days before your test to see which restrictions apply to you. Make sure to follow all pre-testing instructions so that your results are as accurate as possible.
Usually COPD tests are performed independently of your doctor. Blood tests are performed at a testing center and samples are sent to a lab for study. Results can often be obtained within a couple of days or, at most, a couple of weeks.
Results of spirometry tests also take a couple of days to reach your doctor, though your doctor may be able to see them the same day if there’s a rush. The same is true of CT scans and other imaging tests.
Genetic testing tends to take a couple of weeks.
Results of a sputum culture can take anywhere from a day or two to a couple of weeks. The length of time depends on the type of condition being investigated.
Waiting for results can be difficult, but getting accurate test results is critical to properly diagnosing your condition and establishing an effective treatment plan.