How Is COPD Diagnosed?

Chronic obstructive pulmonary disease (COPD) is a group of chronic, progressive lung diseases that make it difficult to breathe. Emphysema and chronic bronchitis are the main types of COPD. COPD is diagnosed based on your signs and symptoms, history of smoking and exposure to lung irritants, family history, and test results. 

If you have symptoms of COPD or known risk factors, your healthcare provider may perform a physical examination and order tests—including spirometry (breathing test), blood work, imaging tests, and other lung function tests. 

If your primary care provider suspects you might have COPD, they may refer you to a pulmonologist—a doctor who specializes in diagnosing and treating diseases related to the respiratory system. 

Physical Examination and Medical History 

The first step in diagnosing COPD is visiting your healthcare provider for a physical examination and assessment of your symptoms. They will thoroughly review your medical history and ask if you: 

• Have ever smoked or currently smoke 
• Have current or past exposure to lung irritants, like dust, air pollution, secondhand smoke, or chemical fumes
• Have family members with COPD
• Have symptoms that may be a sign of COPD, such as chronic shortness of breath or a lingering cough with or without mucus (phlegm) 

Your healthcare provider will also perform a physical examination to look for signs of COPD. They will use a stethoscope to listen for crackling or wheezing in your lungs as you breathe.

Spirometry

Spirometry is the main test used to diagnose COPD and establish the stage of the disease. Spirometry is a non-invasive lung function test that measures the maximum amount of air you can hold in your lungs and blow out. It also measures how quickly you can blow the air out.

A spirometry test measures:

• Forced vital capacity (FVC): How fast you can expel the air from your lungs 
• Forced expiratory volume - 1 second (FEV1): How much air you can expel from your lungs in one second after taking a deep breath 
• FVC/FEV1 ratio: This number is FEV1 divided by the FVC—the percent of air in the lungs that can be breathed out in the first second. Anything lower than 70% indicates COPD. 

To perform this test, you will take a deep breath and then blow as hard as possible into a mouthpiece and tubing connected to a spirometer (small machine). This process will be repeated three or more times to get the most accurate results. The technician may give you a medicine that helps open your airways and then repeat the test. They will compare your test results to see if your breathing improved with the medicine. 

Some people may feel dizzy or lightheaded during the test because it requires fast and hard breathing. You may feel tired afterward or cough more than usual. Tell the technician if you experience any uncomfortable symptoms.

Six-Minute Walk Test

The six-minute walk test is a quick measure of how your heart and lungs respond to light exercise. Before you start to walk, your blood pressure, pulse, and oxygen levels will be taken before you begin to walk. During this test, you will walk at your normal pace for six minutes. You may be instructed to walk to a certain area of your healthcare provider’s office, then turn around and walk back until the six minutes are up. 

Your test results are compared to what is considered normal in people who are the same age, gender, height, and weight as you. This test can help your provider determine if more testing is needed to diagnose COPD.

Blood Tests 

Blood tests can help your healthcare provider determine if your symptoms are caused by other conditions that have similar symptoms to COPD, measure how your lungs are functioning, and determine if you have a genetic predisposition to COPD. 

• Complete blood count (CBC): A complete blood count (CBC) test can help your doctor determine if you have an infection or low iron (anemia).
• Arterial blood gas (ABG): This test measures how much oxygen and carbon dioxide are in your blood. High levels of carbon dioxide in the blood can signal that your lungs are not functioning as well as they should. This test can also help your healthcare provider determine if you need oxygen therapy. 
• Alpha-1 antitrypsin (AAT) deficiency: AAT is a protein that helps protect the lungs. AAT deficiency is a genetic condition that can increase the risk of COPD. People with this inherited condition have lower levels of AAT and are more vulnerable to lung damage.

Imaging 

Imaging scans provide pulmonologists with pictures of your lungs and other structures in your chest. 

Computed Tomography (CT) Scan 

A chest computed tomography (CT) scan is a non-invasive, painless imaging test that takes detailed pictures of your lungs and other structures in your chest. Computers combine the pictures to create three-dimensional (3D) models that show the structure of your lungs. Doctors use these to determine the cause of symptoms like shortness of breath or chronic cough. 

For this test, you will lie still on a table that will be placed into the CT scanner. You will be awake and asked to hold your breath for a few seconds while the pictures are taken. Sometimes, a contrast dye (iodine-based) is injected into a vein in your arm before the imaging test.

Chest X-ray 

A chest X-ray is a quick and non-invasive test that takes pictures of the structures in and around your chest, including the lungs. This test can help your healthcare providers look for signs of conditions like pneumonia or lung cancer. It can also help them check for lung tissue damage and scarring. 

Late-stage COPD causes changes to the lungs and heart that can be detected by X-ray, including: 

• Enlarged heart due to right-sided heart failure 
• Lung damage (bullae) can develop as COPD progresses 
• Flat diaphragm due to lung hyperinflation 

Stages of COPD 

When you get a COPD diagnosis, a pulmonologist will use the Global Initiative for Chronic Obstructive Lung Disease (GOLD) report to assess the stage (grade) of the disease. This helps them determine the best course of treatment to manage symptoms and slow disease progression. 

Factors that are considered to determine the stage of COPD include:

• Spirometry test results 
• Your symptoms and how much and how often they impact your life 
• Your risk of exacerbations (flare-ups), which is when your symptoms suddenly get worse

Pulmonologists can use this information to classify your COPD with a number from Stage 1 to Stage 4 and a letter from Group A to Group D. 

COPD stages include:

• Stage 1 (Mild COPD): FEV1 is 80% or higher
• Stage 2 (Moderate COPD): FEV1 is between 50% to 79% 
• Stage 3 (Severe COPD): FEV1 is between 30% to 49%
• Stage 4: (Very severe COPD): FEV1 is less than 30% 

Your stage will also include a group letter: 

• Group A: You have few symptoms, one or fewer exacerbations, and no hospitalizations in the past year. 
• Group B: You have more symptoms, zero to one exacerbation, and no hospitalizations in the past year. 
• Group C: You have few symptoms, two or more exacerbations per year, and/or one or more hospitalizations in the past year. 
• Group D: You have more symptoms, two or more exacerbations per year, and/or one or more hospitalizations in the past year.

Screening for Related Conditions

Many different medical conditions can cause symptoms similar to those of COPD. Your healthcare provider will use different diagnostic tests to determine whether your symptoms are caused by COPD or another condition, such as: 

• Asthma
• Bronchiectasis
• Bronchiolitis obliterans
• Interstitial lung disease 
• Heart failure 
• Lung cancer
• Tuberculosis 

A Quick Review

COPD is diagnosed based on your symptoms, medical history, exposure to lung irritants, family history, and test results. Tests commonly used to diagnose COPD include spirometry (breathing test), blood tests, imaging tests such as a CT scan or chest X-ray, and a six-minute walking test. 

If you are diagnosed with COPD, your healthcare provider will determine the stage (grade) based on how your lungs are currently functioning, your symptoms and how they impact your life, and your risk of exacerbations (flare-ups).