Pulmonary Function Test (PFT): A Simple Test to Check How Well Your Lungs Work – Dr. Dipak Viradia

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Pulmonary Function Test (PFT): A Simple Test to Check How Well Your Lungs Work – Dr. Dipak Viradia

October 17, 2026

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Breathlessness, a cough that won’t go away, or wheezing can come from many different conditions. Just as a blood pressure check measures your heart’s pressure, a Pulmonary Function Test (PFT) measures how well your lungs are working. In this video, Dr. Dipak Viradia, Chest Physician & Intensivist, explains what PFT is, who needs it, and what to expect.

What Is a PFT?

A PFT is a set of breathing tests. The most common one is spirometry, which measures:

  • How much air you can breathe out after a deep breath (FVC)
  • How fast you can breathe it out in the first second (FEV1)
  • The ratio between the two

These numbers show whether your airways are narrowed, as in asthma or COPD (an obstructive pattern), or whether your lungs can’t expand fully, as in lung fibrosis or chest wall problems (a restrictive pattern).

Often, the test is repeated 15–20 minutes after an inhaler (bronchodilator) to see if your breathing improves. Significant improvement helps confirm asthma.

Who Should Get a PFT?

  • People with breathlessness on walking or climbing stairs
  • Cough lasting more than 3 weeks, or wheezing and chest tightness
  • To diagnose asthma or COPD, and to monitor treatment over time
  • Smokers and former smokers, even without symptoms
  • People exposed to dust, smoke or chemicals at work, such as in textile, diamond or construction work
  • Patients with lung fibrosis, past TB or other lung diseases
  • Before certain surgeries, to check lung fitness

How the Test Is Done

  1. You sit comfortably, and a soft clip is placed on your nose.
  2. You seal your lips around a mouthpiece connected to the spirometer.
  3. You take the deepest breath possible, then blow out as hard and fast as you can, until you can’t blow any more.
  4. This is repeated a few times to get accurate results.
  5. If needed, you’re given an inhaler and the test is repeated after 15–20 minutes.

The test is painless. Some people feel briefly tired or lightheaded from the deep breathing, which passes quickly.

How to Prepare

  • Ask your doctor whether to stop your inhalers before the test, and for how long. Don’t stop them on your own.
  • Avoid smoking for at least a few hours before the test.
  • Avoid a heavy meal just before the test.
  • Wear loose, comfortable clothing.
  • Tell the staff if you’ve recently had a heart attack, eye, chest or abdominal surgery, a collapsed lung, or coughing up blood, as the test may need to be postponed.

Why PFT Matters

PFT gives objective numbers instead of guesswork. It confirms the diagnosis, shows how severe the condition is, helps choose the right treatment, and tracks whether your lungs are improving over time. It can also pick up lung damage before symptoms appear, especially in smokers.

Dr. Dipak Viradia
Chest Physician & Intensivist | Interventional Pulmonologist & ECMO Specialist
Rudrax Chest Clinic, 301, Solaris Royce, Opp. Old RTO, Athwagate, Ring Road, Surat – 395001
Appointment: +91 75676 19985
Website: www.drdipakviradia.com

Frequently Asked Questions

A Pulmonary Function Test is a simple breathing test that measures how much air your lungs can hold and how quickly you can breathe out, helping diagnose conditions like asthma, COPD and lung fibrosis.

No. It only involves breathing into a mouthpiece. Some people may feel briefly tired or lightheaded from the deep breaths.

Spirometry usually takes about 15–30 minutes, including the repeat test after an inhaler if needed.

Sometimes. Your doctor will tell you which inhalers to pause and for how long. Don’t stop them without advice.