Breathing is something most people take for granted—until it becomes difficult. When patients experience shortness of breath, chronic coughing, or unexplained fatigue, pulmonary function tests (PFTs) play a crucial role in helping healthcare providers understand what’s happening inside the lungs.
These tests measure how well your lungs work, including how much air they can hold, how quickly you can exhale, and how efficiently your lungs transfer oxygen into your bloodstream.
By analyzing this data, your doctor can diagnose or monitor lung diseases, assess the severity of respiratory symptoms, and design the most effective treatment plan for your condition.
How Pulmonary Function Tests Help Diagnose Breathing Issues: What Are PFTs?
Pulmonary function tests, sometimes called lung function tests, are a group of noninvasive breathing tests that evaluate your lung capacity, airflow, and gas exchange. They’re often used to detect or monitor conditions like asthma, chronic obstructive pulmonary disease (COPD), interstitial lung disease, or cystic fibrosis.
Depending on your symptoms and health history, your provider may recommend one or more of the following tests:
- Spirometry test: Measures how much air you inhale and exhale, and how quickly you can exhale.
- Lung volume test (Body Plethysmography): Determines the total volume of air your lungs can hold.
- Diffusion capacity test: Measures how well your lungs transfer oxygen and carbon monoxide between the lungs and blood, including how much carbon monoxide is absorbed by the lungs to assess lung function.
- Six-minute walk test or cardiopulmonary exercise test: Evaluates how your lungs, heart, and muscles respond to physical activity.
Why Pulmonary Function Testing Is Important
1. Early Detection of Lung Diseases
Early diagnosis is key to managing chronic respiratory issues. Pulmonary function testing can reveal abnormal lung function long before noticeable symptoms appear. For example, patients exposed to smoke, pollutants, or occupational hazards may show reduced lung capacity even without obvious breathing problems.
Detecting abnormal lung function early allows doctors to recommend lifestyle changes, medications, or breathing therapies that can prevent long-term damage.
2. Evaluating Symptoms and Measuring Lung Performance
If you’re experiencing trouble breathing, a chronic cough, or chest tightness, pulmonary function tests help determine whether your symptoms stem from asthma, COPD, restrictive lung disease, or another respiratory condition.
Tests such as forced vital capacity (FVC) and forced expiratory volume (FEV1) measure how much and how quickly air moves through your airways, helping your healthcare provider determine whether airflow is restricted.
3. Monitoring Chronic Respiratory Conditions
For patients already diagnosed with conditions like chronic obstructive pulmonary disease or interstitial lung disease, lung function tests are essential for tracking disease progression. Regular testing helps determine whether current treatments—such as inhalers, oxygen therapy, or pulmonary rehabilitation—are working as intended.
Your doctor can compare past test results with new ones to see if lung function is stable, improving, or declining. This ongoing monitoring ensures your treatment remains effective and responsive to your body’s needs.
4. Assessing Fitness Before Surgery or Other Treatments
Before undergoing major surgery, particularly those involving the heart or lungs, doctors may order pulmonary function testing to evaluate whether your lungs can handle anesthesia and recovery stress.
These results also guide treatment planning for patients with heart disease or other chronic health issues, helping reduce the risk of postoperative complications.
5. Evaluating the Effectiveness of Breathing Medicines
Spirometry tests and lung volume measurements allow healthcare providers to see how your lungs respond to bronchodilators or other breathing medicines.
For example, if airflow improves significantly after using an inhaler, it confirms that airway constriction was the main cause of your symptoms. This helps fine-tune your medication plan and ensures the best possible symptom relief.
Types of Pulmonary Function Tests
There are several different types of pulmonary function tests (PFTs) that help your healthcare provider check lung function and diagnose a variety of lung diseases. Each test measures a specific aspect of how your lungs work:
- Spirometry: This is one of the most common functional tests. Spirometry measures how much air you can inhale and exhale, as well as how quickly you can force air out of your lungs. It’s especially useful for detecting airway symptoms and narrowing.
- Lung volume tests (Body Plethysmography): These tests determine your total lung volume, or how much air your lungs can hold at their fullest. Body plethysmography is a specialized test that measures all the air in your lungs, even the air that remains after you exhale.
- Diffusion capacity tests: The diffusion capacity test, often using a small amount of carbon monoxide, assesses how well your lungs transfer gases, such as oxygen, from the air into your blood. This is important for detecting problems with how your lungs absorb oxygen.
- Cardiopulmonary exercise tests: These exercise tests evaluate how your lungs, heart, and muscles respond to physical activity. They can help identify whether symptoms like shortness of breath are due to lung or heart problems.
- Other tests: Additional pulmonary function tests, such as the six-minute walk test, can assess your endurance and oxygen saturation during activity.
By combining results from these different pulmonary function tests, your healthcare provider can get a complete picture of your lung volumes, airflow, and gas exchange, helping to diagnose and manage a wide range of lung conditions.
Preparation for Pulmonary Function Tests
Proper preparation is key to getting the most accurate results from your pulmonary function tests. Your healthcare provider will give you detailed instructions before your appointment. You may be asked to avoid smoking, strenuous exercise, or eating a heavy meal for several hours before your function tests. Certain medications, especially inhalers or breathing medicines, might need to be paused temporarily. Always check with your provider before making any changes.
Wear comfortable, loose-fitting clothing to your appointment, as you may need to take deep breaths or perform exercise tests. Arrive on time and let your healthcare provider know about any recent illnesses, ongoing health conditions, or concerns you have before the test begins. Following all preparation guidelines ensures your pulmonary function testing provides the most reliable and useful test results for your care.
How Pulmonary Function Tests Work
During a pulmonary function test, you’ll typically sit in a sealed booth or use a mouthpiece connected to specialized equipment. In the sealed booth, air pressure and air pressure changes are measured during lung-volume testing (body plethysmography) to assess lung function. You’ll wear nose clips to prevent nasal airflow from affecting the measurements and to ensure all air moves through your mouth during testing.
You may be asked to:
- Take a deep breath and exhale as forcefully as possible.
- Breathe normally to measure your tidal volume and functional residual capacity.
- Inhale a small amount of carbon monoxide or helium to assess lung diffusion capacity (how efficiently your lungs absorb oxygen).
Some tests, like the six-minute walk test, measure how your breathing responds to exercise, giving a fuller picture of your lung and heart function.
Risks of Pulmonary Function Tests
Pulmonary function tests are considered very safe, but, as with any medical procedure, there are potential risks. Most people complete these function tests without any problems, but you might feel lightheaded, dizzy, or short of breath during certain breathing maneuvers. Occasionally, coughing or an asthma attack can be triggered, especially if you have a history of lung disease.
Rarely, pulmonary function testing can cause a collapsed lung (pneumothorax), particularly in people with certain underlying lung conditions. If you have had a recent heart attack, bulging blood vessel, or other heart problems, it’s important to tell your healthcare provider before your test.
Always let the respiratory technologist know right away if you feel unwell during testing so they can help you stay safe and comfortable.
What the Test Results Mean
Your pulmonary function test results are compared to normal values based on age, sex, height, and ethnicity. A lower-than-expected result may indicate obstructive or restrictive lung disease.
- Obstructive patterns (e.g., asthma, COPD): Difficulty exhaling air due to narrowed airways.
- Restrictive patterns (e.g., fibrosis, scarring): Reduced lung volume because the lungs can’t fully expand.
Your healthcare provider will interpret these findings, explain what they mean, and design a treatment plan tailored to your specific diagnosis.
Who Should Get Pulmonary Function Tests?
You may benefit from PFTs if you:
- Experience shortness of breath or a chronic cough
- Have a history of smoking or exposure to lung irritants
- Are being treated for asthma, COPD, or lung infections
- Need to assess lung capacity before surgery
- Have unexplained fatigue or exercise intolerance
Regular lung function testing can be especially valuable for patients with ongoing respiratory infections, those using portable oxygen, or individuals recovering from COVID-19 and other respiratory illnesses.
Follow-Up Care After Pulmonary Function Tests
Once your pulmonary function testing is complete, you can usually return to your normal activities, including exercise and taking any medications your healthcare provider may have paused for the test. If you experienced dizziness or lightheadedness during the function test, your provider will monitor you until you feel better.
Your healthcare provider will review your pulmonary function test results and compare them to normal values for your age, sex, height, and ethnicity. Suppose your results are outside the normal range or differ from past test results. In that case, your provider may recommend further testing to evaluate conditions such as chronic obstructive pulmonary disease (COPD), interstitial lung disease, or other lung diseases. Together, you’ll discuss your treatment plan and any follow-up care needed to manage your lung health and ensure the best possible outcomes.
FAQ
Are pulmonary function tests painful?
No, pulmonary function testing is completely noninvasive. You might feel short of breath during certain breathing maneuvers, but discomfort is minimal and temporary.
How long does a pulmonary function test take?
Most tests take between 30 and 60 minutes, depending on how many measurements are needed and whether exercise tests are included.
Can I eat or take medications before the test?
Your healthcare provider will give specific instructions. Typically, you may be asked to avoid smoking, heavy meals, or certain medications (like inhalers) before the test to ensure accurate results.
What if my test results are abnormal?
Abnormal results don’t always mean you have a serious lung disease. Your doctor will interpret the findings in context with your medical history and may recommend further testing or treatments.
Conclusion
Your lungs play a vital role in your overall well-being—don’t wait until breathing becomes difficult to take action. Pulmonary function tests offer valuable insights that can lead to earlier diagnosis, more effective treatment, and lasting peace of mind.
At Blue Point Medical Group, our respiratory specialists use advanced pulmonary function testing technology to deliver accurate results and compassionate care.
Schedule your pulmonary function test today and take control of your breathing health with expert guidance every step of the way.