Pulmonary Function Test (PFT) and Spirometry in Hyderabad

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If your doctor has written “PFT” on a prescription, it doesn’t involve a blood sample or a scan. It’s a breathing test. You sit in a chair, put your lips around a mouthpiece, and breathe the way a technician coaches you to. In Telugu, it’s often called ఊపిరితిత్తుల పనితీరు పరీక్ష, a lung function test.

It’s one of the most useful tests in lung medicine, and one of the most under-used. In the Global Asthma Network study in India, about 82% of people with current wheeze had never been diagnosed with asthma. A breathing test is usually what’s missing.

Spirometry measures two main things:

• FVC (forced vital capacity): the total amount of air you can blow out after the deepest breath you can take
• FEV1 (forced expiratory volume in 1 second): how much of that air comes out in the first second

The FEV1/FVC ratio shows whether the airways are narrowed. When the airways are narrowed, as in asthma or COPD, air can’t get out quickly, so FEV1 drops more than FVC and the ratio falls.

In a spirometry with bronchodilator (reversibility) test, you do the test, take a few puffs of a reliever inhaler, wait 15 minutes, and do it again. A clear improvement suggests asthma. For asthma, GINA’s 2026 report uses an increase of at least 12% and 200 mL in FEV1. Little or no improvement fits COPD better.

“PFT” can mean just spirometry, or a full set of tests. Your doctor picks the ones you need:

A PFT is usually required when:

• You have a cough, wheeze or breathlessness that’s lasted more than a few weeks, or keeps coming back
• Asthma or COPD is suspected. Neither should be diagnosed without a breathing test. GOLD (the international COPD guideline) requires spirometry to confirm COPD.
• You already have asthma or COPD, and need to check how well treatment is working (usually once a year, or after a change in treatment)
• A CT scan shows ILD, fibrosis or emphysema, and the extent needs measuring
• You’re about to have major surgery, especially chest or upper-abdominal surgery, and need lung fitness clearance
• You smoke or have smoked, or have worked with dust, fumes or chemicals, and want to check your lungs
• You’re on a medicine that can affect the lungs, such as amiodarone, methotrexate or some cancer treatments, and need monitoring
• You’re having follow-up after TB, COVID or a severe pneumonia, and breathlessness hasn’t settled

asthma diagnosis

Spirometry is the test that tells asthma and COPD apart, and it’s how both are monitored. For the detail on how the results differ, read.

asthma vs COPD: what a lung test shows

• Height and weight are measured. Your results are compared with people of the same age, sex and height.
• Sitting comfortably, you put on a soft nose clip, so all the air goes through the mouthpiece.
• The technician coaches you: “breathe in as deeply as you can… now BLAST it out… keep going, keep going…” You blow out hard for at least six seconds.
• This is repeated at least three times. International standards require consistent, repeatable blows for a valid result. Most people do it 3–8 times.
• If a bronchodilator test is ordered, you take 4 puffs of a reliever inhaler through a spacer, wait about 15 minutes, and repeat the blows.
• For lung volumes, you sit in a clear, phone-booth-like cabinet (the body box) and pant gently against a mouthpiece for a few seconds. The door is closed, but you can see out, and it opens easily.
• For DLCO, you breathe in a harmless gas mixture, hold your breath for about 10 seconds, then breathe out.

You may feel a bit light-headed or tired from the forced blowing. That passes in a minute or two.

• No fasting needed. Eat a light meal; just avoid a heavy one in the 2 hours before.
• Don’t smoke (including vapes and hookah) for at least 1 hour beforehand.
• Avoid alcohol for 4 hours, and heavy exercise for 30 minutes before the test.
• Wear loose clothing that doesn’t restrict your chest or tummy.
• Inhalers: ask when you book. If the test is to diagnose asthma or COPD, you may be asked to skip your reliever (and sometimes long-acting) inhalers for a few hours beforehand. If the test is to check how well treatment is working, you may be asked to take them as usual. Never stop a prescribed medicine on your own.
• Bring: your inhalers, previous PFT reports, and your CT scan report if you have one.
• Reschedule if you’ve had chest, abdominal or eye surgery in the last few weeks, a recent heart attack, coughed up blood recently, or have a chest infection. Your doctor will advise.

Dr. Kishan reviews the report with you. These are the numbers you’ll see:

Modern reports increasingly use z-scores and the lower limit of normal rather than fixed “80% predicted” cut-offs. This follows the 2022 ERS/ATS technical standard on interpreting lung function tests. It reduces both over-diagnosis in older people and under-diagnosis in younger people.

• Obstructive: the airways are narrowed, so air can’t get out quickly (low FEV1/FVC). Typical of asthma, COPD and bronchiectasis.
• Restrictive: the lungs can’t fill fully (low lung volumes, normal or high ratio). Typical of ILD and fibrosis, chest wall problems, obesity and some muscle conditions. It needs lung volumes to confirm, because spirometry alone can only suggest it.
• Mixed: features of both.

What changes the price:

• Which tests: spirometry alone costs less than a full PFT with lung volumes and DLCO.
• The setting: the hospital or the clinic.

Only the tests your symptoms need are recommended.

Insurance: outpatient lung function tests are usually covered only if your policy includes OPD or diagnostic benefits. Tests done during a hospital admission are normally covered.

Children aged about 5–6 and above can usually do spirometry with good coaching . Impulse oscillometry and FeNO are easier for younger children, because they only need normal breathing or one steady breath. Tests are useful for childhood asthma, recurrent wheezing and chronic cough.