Pulmonary Function Tests

Pulmonary function tests (PFT) show how well your lungs work by measuring the air exchange. With the help of these investigations, your pulmonologist can assess respiratory function across a range of clinical situations. These pulmonary tests give a clear picture of lung health and what breathing problems might exist. 

Pulmonary function tests measure your lungs' volume, capacity, flow rates & gas exchange. The results become a guiding stone for treatment options & check how well your lungs are responding to treatments. Each person has different normal values for these tests. Measurements like forced vital capacity (FVC) and forced expiratory volume (FEV1) play a crucial role in getting accurate results.

This article explains everything about pulmonary function testing, from how to prepare and what happens during the procedure to understanding your results and what they mean for your respiratory health.

What is a Pulmonary Function Test?

Pulmonary Function Tests (PFTs) are non-invasive breathing tests that show how well your respiratory system works.  These tests give a clear picture of your lung capacity, breathing rates, and how oxygen moves between your lungs and blood.

PFTs combine different tests to create a full picture of your lung health.  Spirometry (it is the most common test) measures the amount and speed of air you breathe out. Your doctor might also check lung volume and run tests to see how well oxygen reaches your blood. The best part is that you won't need any invasive procedures for these examinations.

When Should You Get the Pulmonary Function Test Done?

You should ask your doctor about PFTs if you notice:

• Persistent coughing or wheezing
• Shortness of breath
• Chest tightness or pressure

Your doctor might suggest these tests before surgery, after exposure to harmful substances, or during regular checkups.

Why Do I Need a Pulmonary Function Test

Doctors use these tests to: 

• Diagnose conditions like asthma, COPD, pulmonary fibrosis, and sarcoidosis
• Help track how diseases progress 
• Show if the treatment is working
• Help assess surgery risks 
• Reveal any lung damage from environmental factors 
• Guides your treatment plan 
• Helps monitor your breathing health over time

Procedure for Pulmonary Function Test

When you go in for the test, your doctor will walk you through what's about to happen. You will be asked to sit down and wear a nose clip, which just helps make sure no air escapes. Then you will breathe through a tube attached to the machine. The technician will guide you through a few different ways of breathing, like taking a deep breath, blowing out hard, or sometimes breathing quickly. If needed, you might get medicine to see if your lungs respond, and then you will have to undergo the test again. They will keep an eye on you the whole time in case you feel dizzy or uncomfortable. Once you're done, a doctor will look at your results and figure out what they mean for your care.

How to Prepare for the Pulmonary Function Test?

Your test will be more accurate if you follow these steps before your appointment:

• Stay away from smoking for 4-6 hours
• Keep your meals light
• Skip caffeine for at least 4 hours
• Choose loose, comfortable clothes
• Take it easy on exercise before the test
• Bring your medication list
• Talk to your doctor about stopping certain medications temporarily, especially bronchodilators

Values of Pulmonary Function Test Procedure Results

Your age, height, sex, and race affect what's considered normal. Doctors compare your results to predicted values for people like you. A healthy adult's results usually show:

• FEV1/FVC ratio - above 0.70
• FEV1 and FVC - exceeding 80% of the predicted value
• Total lung capacity - above 80% of the predicted value

What Abnormal Results Mean

Low numbers often point to lung or chest problems. A low FEV1/FVC ratio suggests obstructive diseases like asthma, emphysema, or chronic bronchitis. Restricted lung capacity might indicate the below-listed conditions:

• Extreme obesity
• Lung fibrosis
• Sarcoidosis
• Scleroderma.

Conclusion

The name "Pulmonary Function Tests" might sound a bit complicated to you. In reality they are simple breathing tests that can tell how your lungs are doing. If you have been coughing, wheezing or finding it hard to catch your breath, it is worth asking your doctor about these tests. They can give you a clearer idea of the picture inside your chest. Your doctor will look at numbers (like FEV1 and FVC) to figure out what kind of breathing problem you might have. These tests also help your doctor keep an eye on your lungs over time so you will know if things are getting better (or if you need to try something new). 

Remember, what’s normal for one person might not be for another. Age, height, and even your medical history can change what your results mean. Your doctor will walk you through what your numbers say about your own health and help you find the best way to breathe easier.

FAQs

1. What does a Pulmonary Function test mean if it's high?

High PFT values show your lungs work great. When your results are above predicted values, it means your lungs move air well and handle oxygen exchange perfectly. These high readings shouldn't worry you (they just mean your lung capacity is better than most people's).

2. What happens if the Pulmonary Function test is low?

Low values often point to lung problems. Tests showing below-normal results indicate higher risks for both overall and lung-related complications. A low FEV1/FVC ratio (below 70%) might mean you have conditions like asthma or COPD. Low FVC numbers could suggest restrictive conditions like pulmonary fibrosis.

3. Is it better to have a high or a low Pulmonary Function test?

Higher values are definitely better. They show your lungs work at their best. Lower values link to shorter life spans and might signal breathing problems.

4. What is a normal Pulmonary Function test level?

Your results should show:

• FEV1/FVC ratio - above 0.70
• FEV1 and FVC - above 80% of the predicted value
• Total lung capacity - over 80% of predicted

5. What not to do before a pulmonary function test?

Stay away from:

• Smoking on your test day
• Big meals 2 hours before
• Alcohol 4 hours before
• Hard workouts 30 minutes before
• Caffeine on test day
• Clothes that squeeze your chest

6. Is a pulmonary function test painful?

You can relax - PFT tests don't cause any pain. The test only requires you to do some breathing exercises that measure your lung capacity. Some patients might feel slightly short of breath, dizzy, or have brief chest discomfort, but these feelings don't last long. The medical team watches you carefully throughout the test and can stop it if needed.

7. How long does a pulmonary function test take?

Simple lung function tests usually take 15-45 minutes. The actual time depends on:

• The specific tests your doctor orders
• Your health conditions
• Whether you need to rest between test parts

Tests with multiple components might take up to 60 minutes.

8. Can a pulmonary function test detect asthma or COPD?

These tests are excellent at diagnosing breathing problems. They help doctors identify asthma and COPD through specific breathing patterns. To diagnose asthma, doctors often run tests before and after giving bronchodilator medication. A major improvement afterwards points strongly to asthma.

9. Is fasting required before a pulmonary function test?

You don't need to fast completely, but some food restrictions help get accurate results. Don't eat heavy meals within 2 hours of the test. Light snacks are fine, but avoid caffeine for at least 4 hours before. The doctors also suggest skipping alcohol on your test day.