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Diagnosis of Chronic Obstructive Pulmonary Disease (COPD)
There are no specific tests to confirm COPD. Instead, your doctor will use your symptoms, risk factors, and test results to determine if it is present. COPD cannot be found before irreversible lung damage has occurred. The earlier it is detected, the sooner steps can be taken to slow further damage.
Your doctor will ask you about your symptoms and medical history. A physical exam will be done. Your history and physical exam will provide the most important information for the diagnosis of COPD. Other tests may be done to look for more signs of COPD and assess the changes to the lung. These tests can also show how impaired your breathing may be.
Pulmonary Function Tests
These function tests can show how well your lungs are working. There are a number of different test options. These tests are painless and non-invasive. You will be asked to breathe into a tube called a spirometer. It will measure how much air your lungs can hold. It will also measure your ability to move air in and out of your lungs in a certain period of time. Your results are compared with typical findings of a healthy person your age and similar height. All of this information will show how much your lung function has declined.
Tests may also be done after you have been given certain medication. This is to see if this type of treatment is effective for you.
Pulmonary function measures include:
- Forced vital capacity (FVC)—The maximum volume of air that you can forcibly blow out after inhaling as deeply as possible.
- Residual volume (RV)—The amount of air that stays in the lungs after a breathing out as much as possible. With COPD, air is trapped in the damaged lung and cannot be exhaled normally. RV can increase dramatically with COPD.
- Total lung capacity (TLC)—The total amount of air the lungs are capable of holding. It is the combination of FVC and RV.
- Forced expiratory volume in 1 second (FEV 1 )—The amount of air that can be forcibly blown out in one second. It is used to show the rate of air movement out of the lungs. FEV 1 often declines a very small amount per year. The decline can be several times greater in people with COPD. This is especially true if they continue to smoke.
- Peak expiratory flow (PEF)—Maximum speed you can blow out after inhaling as deeply as possible.
Carbon Monoxide Diffusing Capacity
This test measures how well a gas can pass from your lungs and into your blood. You will be asked to breath in air containing a very small amount of carbon monoxide. When you breathe out, the carbon monoxide in your breath will be measured. Your doctor will look at the difference between amount of gas that was inhaled and the amount you exhaled. The missing gas will have been passed into your blood. This reflects how easily oxygen can get into your blood from your lungs.
A small clip will be placed on your finger. It can quickly show how much oxygen is in your blood.
- Arterial blood gases—Shows the amount of oxygen and carbon dioxide in your blood.
- Levels of alpha-1-antitrypsin—This is an important protein that helps to protect the lungs from damage. A certain genetic defect may cause low levels of this protein. It may be low in people with a certain genetic defect. Low levels may increase the risk of getting COPD at an early age even in those who have never smoked.
COPD. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115557. Updated September 1, 2018. Accessed October 15, 2018.
How is COPD diagnosed? National Heart, Lung, and Blood Institute (NHLBI) website. Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/copd/diagnosis.Accessed October 15, 2018.
Patient Education: Teaching the Patient with Chronic Obstructive Pulmonary Disease (COPD). EBSCO Nursing Reference Center website. Available at: http://www.ebscohost.com/nursing/products/nursing-reference-center. Updated March 28, 2018. Accessed October 15, 2018.
Qaseem A, Wilt TJ, Weinberger SE, et al; Diagnosis and management of stable chronic obstructive pulmonary disease: a clinical practice guideline update from the American College of Physicians, American College of Chest Physicians, American Thoracic Society, and European Respiratory Society. Ann Intern Med. 2011;155(3):179-191.
- Reviewer: Michael Woods, MD, FAAP
- Review Date: 03/2018
- Update Date: 03/30/2018