The Pulmonary Function Test: What to Know

A doctor listens to a patient's lungs.
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If you’ve been referred to a pulmonologist, you might have some questions about how your first appointment might go. If you’re experiencing problems with your breathing or feeling shortness of breath, the pulmonologist is the specialist who will help you get the answers you need to start your path toward healing.

One of the first — and most basic — tests your pulmonologist might do is called a pulmonary function test (PFT), which measures how efficiently your lungs are working, including how well you are breathing and how effectively your lungs can bring in and exhale oxygen. The results help lead to a diagnosis of many different lung diseases.

Dr. George Torres, MD, pulmonologist at AdventHealth Centers for Pulmonary Disease at Apopka, explains this test and why it can be an important first step in a patient’s journey.

Understanding the Pulmonary Function Test

“The PFT is a good initial test because it’s safer than an X-ray in that it does not expose a patient to radiation, and an X-ray won’t tell you about how the lungs are functioning like this test does,” explains Dr. Torres.

This in-office test can take between 60 and 90 minutes. It measures airflow, or how well you can generate pressure to enter air into and then exhale air out of lungs.

When entering, air flow goes from low to high pressure. Inhaling decreases pressure in the chest and air flows passively into the lungs with active muscular exercise. Then, upon exhale, air is forced out of the lungs.

Dr. Torres says, “The pulmonary function tests also gives us the measurement of gasses involved in the exchange of air, as well as the diffusion capacity, or the accuracy of the transfer of oxygen and carbon dioxide gases in the lungs.”

This information leads specialists like Dr. Torres to explore further diagnostic testing.

“It’s important to specify that the pulmonary function test is suggestive of a diagnosis, but it’s not diagnostic. It’s just one step in the process that guides us to the right diagnostic tests for each patient,” Dr. Torres states.

Types of Lung Diseases

Obstructive lung diseases cause a decrease in airflow. This means that people have a hard time exhaling all of the oxygen out of the lungs, leading to shortness of breath. If this was detected with the PFT, then more diagnostic tests for this group of diseases might be ordered.

Some common obstructive lung diseases include:

  • Asthma
  • Bronchiectasis
  • Chronic obstructive pulmonary disease (COPD) (including chronic bronchitis and emphysema)

The other group of lung diseases is called restrictive. These reduce the ability of the lungs to expand, so they can’t fill with enough air. In this case, the PFT might show a lower than average air volume in the lungs and could lead to further testing for pulmonary fibrosis or other neurological or neuromuscular diseases.

Who Should Have a Pulmonary Function Test?

“This test is done both for clinical and occupational purposes,” says Dr. Torres.

He explains that many firemen and police officers are required to have this type of exam on a regular basis.

In addition, those who smoke or vape might need this test to assess their lung health as recommended by their physician.

Dr. Torres comments, “With vaping it’s still a new situation that’s unfolding and we don’t have all of the information at this time, but we are seeing that it is a potentially very harmful activity that could become a major public health problem.”

Who Should See a Pulmonologist?

Many times, patients are referred to a pulmonologist by their primary care doctor with an unexplained symptom such as a chronic cough, shortness of breath, limitation with exercise or excessive sleepiness.

“If you have any of these symptoms, it’s very important to see a pulmonologist and not let the symptoms worsen. With earlier diagnosis and intervention, we can often preserve health and quality of life with much better outcomes,” says Dr. Torres.

He concludes, “Let your breathing be my problem, not yours. Difficulty breathing can diminish quality of life, and we can offer help to restore that.”

Learn more about AdventHealth Centers for Pulmonary Disease at Apopka or book your appointment today.

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