If you are experiencing symptoms associated with the respiratory system (e.g., shortness of breath, cough, or wheezing), you currently use tobacco products, or you are considering lung or airway surgery, it is likely your specialist will recommend a pulmonary function test in order to assess your lung function.

A Pulmonary Function Test (PFT) is a non-invasive method used to determine how well your lungs function at rest and during exercise.

Let’s examine the most performed PFTs, their primary purposes, what is involved with the procedures, and how the results are discovered. Additionally, we want to discuss where you can receive a high-quality pulmonary function locally.

Types of Pulmonary Function Tests

PFT is an umbrella term that encompasses many different types of tests that measure your lung capacity and function. The most common PFTs are spirometry, cardiopulmonary exercise test, gas diffusion study, and plethysmography.

PFT is an umbrella term that encompasses many different types of tests that measure your lung capacity and function. The most common PFTs are spirometry, cardiopulmonary exercise test, gas diffusion study, and plethysmography.


spirometry test measures the volume and flow of air through your lungs and is used to determine how well your lungs are functioning.


A spirometry test tells your healthcare specialist how strong your lungs are and how well you breathe. It also assists them in diagnosing common conditions, such as asthma and chronic obstructive pulmonary disease (COPD). Spirometry can also determine how well you are recovering from pulmonary illnesses, like pneumonia or COVID-19.


For the test, you will be asked to breathe into a plastic mouthpiece attached to a spirometry machine. The technician will direct you to take a deep breath in and then breathe out as forcefully and quickly as possible until you empty your lungs.

This procedure will be repeated three times to ensure your results are accurate and reproducible. Your pulmonary specialist may administer medicine to you that helps open your airways in order to determine if the medicine may be an effective tool to incorporate into your treatment plan.


Everyone’s lungs are different, so a “normal” result for the test varies from person to person and is based on age, sex, height, weight, and race. The result is considered normal if your score is 80% or more of the predicted value for your specific demographic. A score below 80% is abnormal and you may be required to perform additional tests, such as a chest X-ray or blood screening.

Cardiopulmonary Exercise Test

cardiopulmonary exercise test (CPET), or stress test, measures how well your lungs, heart,
and muscles function during exercise.


This test allows your healthcare specialist to ascertain a variety of cardiac disorders, such as inadequate blood flow, abnormal heart rate, high or low blood pressure, irregular heart rhythm, and blood-pumping issues. The test can also display common lung problems such as asthma, emphysema, bronchitis, and muscular conditions.


For the test, different monitors will be placed on your body, including EKG leads to measure heart rate, a blood pressure cuff, a pulse oximeter to measure blood oxygen level, and a mouthpiece attached to a flow meter to measure your breathing rate and depth.

During the test, you will be directed to either walk on a treadmill or ride a stationary bicycle. Initially, you will be advised to begin slowly (to warm up), and then gradually the treadmill will move faster, or resistance on the stationary bicycle will increase until you stop.

Before stopping the activity, you will be asked to walk or pedal at a slow rate to cool down.


The test will measure different parameters of the body and pinpoint issues with your lungs, heart, and musculoskeletal system.

Gas Diffusion Study

gas diffusion study measures how efficiently your lungs absorb oxygen and release carbon

For this test, you will put on nose clips and be directed to place your lips around the mouthpiece. You will then be required to inhale a small amount of gas mixture containing a safe amount of carbon monoxide as a tracer. Afterward, you breathe this gas out into a tube. A machine, such as a spirometer, will detect the amount of carbon monoxide you exhale.

A diffusion rate that is below normal often reveals that the person is suffering from obstructive lung disease or pulmonary damage, while a diffusion rate that is higher than normal can be indicative of polycythemia (elevated red blood cell count) or bleeding in the lungs.


This test measures changes in volume in different parts of the body, as well as how much air you can hold in your lungs. It is often performed to assess the risk or presence of blood clots in the arms and legs.

For this test, you will sit in a small, clear cabin and breathe into a mouthpiece. As you breathe, the spirometer will detect volume changes in the box which helps measure lung capacity.

Abnormal lung volume is indicative of a disorder that prevents your lungs from holding as much air as they should.

Pulmonary Function Test Near Me

At Lung & Sleep Specialists of North Texas, we offer state-of-the-art diagnostics testing services including pulmonary function tests to give you an accurate diagnosis and treatment plan, in addition to monitoring your lung recovery after illness. Our highly skilled and board-certified pulmonologist, Dr. Olusegun Oseni, MD, FCCP, DABSM is deeply committed to providing advanced and comprehensive treatment for your unique lung or airway issue.

To learn more about pulmonary function tests near you or make an appointment with us, call (817) 594-9993 or use our online request form.


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