PFT chart, oxygen tubes, and dna

Differences Between an Asthma and COPD Diagnosis

Last updated: March 2021

COPD and asthma are both obstructive lung diseases. Classic symptoms of both are shortness of breath, chest tightness, and coughing. The path to getting to a proper diagnosis of both are also similar. But, there are also some key differences. Here is a look at differences between asthma and COPD diagnosis.

The definition of both asthma and COPD

Both asthma and COPD are obstructive lung diseases. These obstructions occur in bronchial airways. These obstructions cause airflow limitation, which can make you feel short of breath. With both diseases, inflammation plays a key role in this inflammation. Exposure to triggers makes this inflammation worse in both diseases.1-2

Key differences between asthma and COPD

Asthma tends to be genetic or hereditary. It’s is defined as a reversible disease. This means that symptoms are reversed with time or treatment. So this makes it very treatable. It's also considered to be a controllable disease. This means symptoms can be prevented. When symptoms do occur, they are mild and easy to control. Control is obtained by working with a doctor and developing an asthma treatment regimen.1-2

COPD is usually caused by chronic exposure to noxious substances in the air. Therefore it’s usually preventable. It’s also treatable. It’s defined as a progressive disease. Some symptoms cannot be reversed and may be present even on good COPD days. The goal here is to minimize symptoms and slow the progression of the disease. This is accomplished by working with a doctor and developing a COPD treatment regimen.1-3

What tests are used to diagnose asthma and COPD?


A lot can be learned by a simple Q & A.

  • Asthma. You have a family history of asthma or allergies. Is the patient an adult or a child. Asthma is the most common chronic disease in children. Asthma is usually diagnosed in childhood but can be diagnosed at any age. Your symptoms vary over time. For instance, periods between attacks may last days, years, months, or even years. Your symptoms may also vary in intensity. They may appear to be worse at night.2
  • COPD. You have a history of exposure to cigarette smoke. You have a history of exposure to noxious substances, such as air pollution at your work. Your symptoms are persistent, such as a cough or shortness of breath that always seems to be present. You may feel more short of breath with exertion that while resting. COPD is usually not diagnosed until after the age of 40. It’s rare for it to be diagnosed in children.

Pulmonary Function Testing (PFT)

This is a breathing test that can help rule in one and out the other. It is a very important test that may point the finger at either asthma or COPD.

  • Asthma. It shows airflow limitation that is reversible with treatment. Lung function may return to normal for your age after attacks. The reversibility of airflow limitation is a key defining factor of asthma. Sometimes this is the only test needed to confirm a diagnosis of asthma. Although, often another test is needed.2 To learn more, read "PFT and Asthma"
  • COPD. It shows airflow limitation that is only partially reversible or not reversible at all despite treatment. Lung function may improve with treatment but never returns to normal for age. Some airflow limitation persists despite treatment. This is the one test that is recommended to confirm a diagnosis of COPD.3


Can prove helpful in diagnosing both diseases.

  • Asthma. It may show hyperinflation during attacks. But, should be normal between attacks.
  • COPD. It may show hyperinflation all the time. With COPD it may also show other marks that indicate COPD

Differential Diagnosis

This is where you rule in one disease by ruling out other diseases.

  • Asthma. COPD must be ruled out. So, this is sometimes hard to do, but a PFT can help. Vocal cord dysfunction, congenital heart disease, and cystic fibrosis are other diseases that may mimic asthma symptoms. So, sometimes efforts are made to rule those out too.2
  • COPD. Asthma must be ruled out. Again, a PFT can really help here. Pulmonary fibrosis, lung cancer, and pneumonia must be ruled out.3

Bronchial Provocation

This is a special test used to diagnose asthma in those who are not currently experiencing symptoms. Medicine is inhaled to induce asthma. A bronchodilator is then given. If symptoms are reversed this is a key indicator that a person probably has asthma. This test is not used to diagnose COPD.

Allergy testing

Allergies are very common in people with asthma. But, not all asthmatics have allergies. Still, allergy testing, especially in children, may indicate a possibility of asthma.3

Exhaled Nitric Oxide (FENO)

This is another test used to diagnose asthma. FENO may be elevated in many people with asthma. This test is not typically done to diagnose COPD.

Different strategies are used to diagnose asthma or COPD

There is no one single test that says asthma or says COPD. For this reason, physicians may use one or a variety of strategies for diagnosing them. For instance, sometimes asthma is defined by history alone. Although, sometimes many different tests may be needed to confirm asthma. Similarly, COPD may be diagnosed based on symptoms alone. However, the best test for diagnosing is a PFT showing persistent airflow limitation.

So, diagnosing both diseases are similar in many ways. But, they are also different. So, listed here are some of the key differences between COPD and asthma diagnosis.

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This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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