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Pulmonary Function Test for Asthma Allergy and COPD

Asthma Allergy and Pulmonology patients at Asthma Allergy Centre Thrissur are tested at second visit by PFT measurement. The tests determine how much air an Asthma or COPD or any Pulmonary disease patient can hold by breathing in to their maximum ; and also  how quickly they can force out or breath out the inhaled air.

The tests needs only 3 really forceful breathing in and blowing out into a tube connected to a tube which is connected to a computer software called Spirometry machine. Surprisingly this simple breathing effort can easily diagnose many lung diseases, measure the severity of lung problems, and check to see how well treatment by the Pulmonologist is working.

Lung function tests are done to:

  • Determine the cause of breathing problems.
  • Diagnose certain lung diseases,and its severity; such as asthma or chronic obstructive  pulmonary disease (COPD).
  • Evaluate a person’s lung function before surgery to find fitness for operation.
  • Check the lung function of a person who is regularly exposed to substances such as air pollution that can damage the lungs.
  • Check the effectiveness of treatmentespecially for asthma and COPD; as well as for other lung diseases.

The testing may take from 5 to 15minutes, depending upon how many tests are done.

How the Test is performed?

Spirometry measures airflow. By measuring how much air you exhale, and how quickly, spirometry can evaluate a broad range of lung diseases. In a spirometry test, while you are sitting, you breathe into a mouthpiece that is connected to an instrument called a spirometer. The spirometer records the amount and the rate of air that you breathe in and out over a period of time.

How to Prepare for the PFT test

Do not smoke for 4 – 6 hours before the test

you need to stop using bronchodilators or inhaler medications

You may have to breathe in medication before or during the test.

How the Test Will Feel?

Since the test involves some forced breathing and rapid breathing, you may have some temporary shortness of breath or lightheadedness. You breathe through a tight-fitting mouthpiece, and you’ll have nose clips.

Why the Test is performed?

Pulmonary function tests are done to:

  • Diagnose certain types of lung disease (such as asthma, bronchitis, and emphysema)
  • Find the cause of shortness of breath
  • Measure whether exposure to chemicals at work affects lung function
  • Check lung function before someone has surgery

It also can be done to:

  • Assess the effect of medication
  • Measure progress in disease treatment

Normal Results

Normal values are based upon your age, height, ethnicity, and sex. Normal results are expressed as a percentage. A value is usually considered abnormal if it is less than 80% of your predicted value.

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Different measurements that may be found on your report after spirometry include:

  • Expiratory reserve volume (ERV)
  • Forced vital capacity (FVC)
  • Forced expiratory volume (FEV)
  • Forced expiratory flow 25% to 75%
  • Functional residual capacity (FRC)
  • Maximum voluntary ventilation (MVV)
  • Residual volume (RV)
  • Peak expiratory flow (PEF).
  • Slow vital capacity (SVC)
  • Total lung capacity (TLC)

What Abnormal Results Mean?

Abnormal results usually mean that you may have some chest or lung disease.

Some lung diseases (such as emphysema, asthma, chronic bronchitis, and infections) can make the lungs contain too much air and take longer to empty. These lung diseases are called obstructive lung disorders.

Other lung diseases make the lungs scarred and smaller so that they contain too little air and are poor at transferring oxygen into the blood. Examples of these types of illnesses include:

  • Extreme overweight
  • Fibrosis of the lungs
  • Lung cancer
  • Sarcoidosis and scleroderma


The risk is minimal for most people. There is a small risk of collapsed lung in people with a certain type of lung disease. The test should not be given to a person who has experienced a recent heart attack, or who has certain other types of heart disease.


Your cooperation while performing the test is crucial in order to get accurate results. A poor seal around the mouthpiece of the spirometer can give poor results that can’t be interpreted. Do not smoke before the test.At Asthma Allergy Pulmnology Centre Thrissur; Professor Dr Kurian Thomas himself is doing the test.( Not by Lab technicians as at most centres in Kerala.)



Asthma Allergy Pulmonology and Chest Centre Thrissur Kerala

Asthma Allergy Pulmonology and COPD Centre Thrissur Kerala

Dr Kurian Thomas MBBS; DTCD; MD ; DNB

Pulmonary Medicine Rtd Professor Medical College Thrissur

Pipe Line Road
Mylipadam, Thrissur

Ph : 0487 2333433
Mob : 9446333433