Chronic obstructive pulmonary disease (COPD) is a progressive condition that slowly decreases lung function over time. The term COPD includes emphysema and chronic bronchitis. When a COPD diagnosis is made, a physician will classify it in stages (mild, moderate, severe, or very severe) according to a person’s symptoms and overall lung function. At any stage of COPD, it’s important to quit smoking and avoid inhaling pollutants like second-hand smoke or anything that may further damage the lungs.     

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COPD Diagnosis

When considering a COPD diagnosis, your physician will ask about your history of smoking and exposure to harmful chemicals and pollutants. They’ll also ask about any difficulty with breathing while in motion, such as when you’re climbing stairs, and while at rest. 

After establishing your risk, your doctor may also use a variety of diagnostic tests to determine the severity of COPD. These tests include: spirometry (lung function test), chest X-rays, CT scans, and blood tests. In some cases, they may analyze the cells in your mucus or sputum to help determine if bacteria is present, or if the cells are abnormal or cancerous.

Despite the variety of tests available, a breathing test that uses an instrument called a spirometer reveals the most accurate details about lung function. Spirometry takes only a few minutes, is painless, and can reveal COPD symptoms even if they’re not yet obvious.

A spirometer measures exactly how much air is expelled from the lungs and how forcefully it’s exhaled. Patients are asked to repeat the test a number of times to determine an average result. Two important values are then established: the forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Those numbers set a baseline for a person’s overall lung function at the time of diagnosis.

The FEV1 recording shows if a person’s exhalations remain weak for a full second. In people who have COPD, that number decreases over time. Those values also directly correlate with each stage of COPD to set a universal standard and to assist in more accurately treating the disease.             

Progression of COPD

After examination and reviewing tests, doctors classify COPD in stages according to its severity. Each stage considers spirometric values as well as signs and symptoms of the disease. The following values reflect recent changes in the universal COPD treatment guidelines set forth by the Global Initiative for Chronic Obstructive Lung Disease (GOLD).

COPD Stage I / Mild

People with Stage I COPD are typically unaware that they have lung disease. Their symptoms of coughing and mucus are frequent, but not chronic. They are not short of breath and usually continue to exercise normally. Their FEV1 numbers are less than 80 percent of normal lung function (FEV1/FVC<80%). Treatment for Stage I COPD is usually a short-acting bronchodilator to be used as needed to open up restricted airways.      

COPD Stage II / Moderate

People with Stage II COPD may experience shortness of breath while exercising, especially when climbing stairs. Most people become aware of COPD at this stage because coughing and mucus production becomes too excessive to ignore. As in Stage I, treatment for Stage II COPD can be both a short-acting bronchodilator to be used as needed as well as one or more long-acting bronchodilator medications. Patients with moderate COPD are also urged to exercise their lungs by keeping active and undergoing pulmonary rehabilitation to maintain lung function. Stage II FEV1 numbers reveal between 50 and 79 percent of normal lung function (FEV1/FVC(50-79%)).   

COPD Stage III / Severe

Stage III COPD can have a serious impact on a person’s daily activities. Increased shortness of breath is experienced during exercise, even when it’s moderate. Flare-ups or exacerbations are more frequent, as is coughing and mucus production. In addition to treating Stage III COPD with one or more bronchodilators and pulmonary rehabilitation, physicians will often add inhaled corticosteroids for periods of exacerbation. Stage III COPD patients also should be vaccinated for pneumonia and seasonal influenza. Stage III FEV1 numbers reveal between 49 and 30 percent of normal lung function (FEV1/FVC<49-30%).

COPD Stage IV / Very Severe

Stage IV COPD is the most serious stage of the disease. Symptoms worsen, ?coughing and mucus production are even more frequent, and any activity, even eating, can be a challenge. Stage IV COPD sufferers often rely on oxygen therapy, but flare-ups from the disease are increasingly serious, even deadly. In addition to a variety of bronchodilators and inhaled corticosteroids, oxygen therapy, vaccinations and antibiotics, treatment may also include surgery to remove damaged lung tissue. Stage IV FEV1 numbers reveal less than 30 percent of normal lung function (FEV1/FVC<30%).