Pulmonary Function Test

Pulmonary Function Test

Pulmonary function tests are investigations that are performed to check how well the lungs are functioning. These tests help you determine how much air enters and leaves the lungs, how much air goes to the blood from the lungs, and how well the lungs perform during exercise. You will be contacted a few days after your test by your healthcare provider with the results.

Pulmonary function tests are a combination of different types of breathing tests that are performed to measure how well the lungs are exchanging air. Your lungs perform the function of taking in air and breathing it out. Pulmonary function tests are of many different types. Some of those are also used to measure how well the lungs absorb oxygen into the blood and how exercise affects the lungs.

Pulmonary function tests are safe investigations that don’t involve putting any instruments or tools inside your body. We offer the best pulmonary function tests in Indore. They are also called lung function tests.

Lung function tests include:

  • Spirometry
    Spirometry is used to measure how much air you can inhale or exhale. It is also used to estimate how much air is there in your lungs.
  • Lung volumes or body plethysmography
    Body plethysmography or lung volumes quantify the different amounts of air that are present in your lungs after various points of inhalation and exhalation.
  • Gas diffusion study
    This study is performed to measure how much oxygen and other gases are transferred from your lungs to your blood.
  • Cardiopulmonary exercise test (CPET)
    This test is performed to measure how well your lungs, heart, and muscles work while you are exercising.

The most common type of pulmonary function test is spirometry.

Your doctor may order pulmonary function tests if you present with airway or lung symptoms including shortness of breath or cough, are undergoing surgery or are exposed to smoke. These symptoms may include:

  • Coughing, especially if you produce phlegm or mucus.
  • Pain, chest tightness, or pressure.
  • Dyspnea or shortness of breath.
  • Difficulty breathing or taking a deep breath.
  • Wheezing.

Even if you lack symptoms, your doctor may order a pulmonary function test as a part of a routine physical examination.

Pulmonary function tests also help your doctor:

  • Identify early changes in the ability of your lungs to transfer oxygen to your blood.
  • Diagnose narrowing in the airways of your lungs.
  • Evaluate if medications may help improve your breathing.
  • Measure the effects of continued smoking on chronic pulmonary diseases.
  • Know your ability to tolerate surgery or other medical procedures.
  • Understand if exposure to certain substances in your environment has affected your lungs adversely.

Pulmonary function tests help your healthcare provider diagnose chronic obstructive pulmonary disease, asthma, narrowing of your trachea, and weakness of your breathing muscles.

Pulmonary function testing is usually performed by a specially trained respiratory therapist.

A pulmonary function test is a simple procedure. It consists of a clear, airtight box, a mouthpiece, soft nose clips, and a tiny electronic machine that is used to measure your airflow.

Before the test, the doctor will ask you to:

  • Wear comfortable and loose clothing that doesn’t squeeze your chest.
  • Stop taking your breathing medicines for a short period.
  • Avoid using tobacco products before your test.
  • Avoid performing any heavy exercise or strenuous activity before your test.

These precautions help ensure that you get accurate results from your pulmonary function test.

Before the pulmonary function test, the doctor will record some personal information of yours, including your weight, height, race, age, and sex. This information will be used by him to determine a typical value for your demographic.

After your information is recorded, your doctor will take you to a room with pulmonary function test equipment and provide you with some information according to the test you are going to undertake.


A healthcare provider will first apply soft clips to your nose that will ensure that you breathe not through your nose, but from your mouth. You will be asked to put your lips around a mouthpiece that connects to a spirometer. Then, the provider will provide you with directions on breathing in and out. Then you will be asked to take deep breaths in and out. You may also take deep breaths in and blow out as fast and hard as possible for your condition.

Body plethysmography

Your nose clips will be put by your healthcare provider and you will be asked to sit in the clear box. Your doctor will close the door and keep it closed for around five minutes. Let your healthcare provider know if you are claustrophobic or you feel uncomfortable in confined spaces. They can take some steps to make you more comfortable during the test. You will be asked to put your lips around a mouthpiece and given instructions on breathing in and out.

As you are breathing, the spirometer will detect volume or pressure changes in the box so that your lung volumes can be measured.

Bronchial provocation test

If you are suffering from asthma, you must know that triggers like smoke, exercise, and dust can make it challenging for you to breathe. A bronchial provocation test can help detect asthma and its severity. During this test, you are asked to inhale a medication that causes narrowing of your airways. Then, you will undergo a spirometry test several times. Your healthcare provider will use the readings to determine how much your airways narrow during an asthma attack.

Gas diffusion study

Your nose clips will be put on by your healthcare provider. You will be asked to put your lips around the mouthpiece and a doctor will give you directions on breathing in and out a small amount of carbon monoxide that is within the safe limits. While you are breathing, the spirometer will measure the amount of carbon monoxide you exhale. This measurement indicates the amount of gas your lungs have absorbed.

Cardiopulmonary exercise stress test

This test is used to measure the strength of the lung and heart. It is usually suggested for people who have lung or heart problems. These conditions sometimes show up only during exercise. During this test, you will be asked to ride a stationary bike or walk on a treadmill. The healthcare provider will monitor your heart rate as your heart beats faster and faster. You will be asked to breathe into a tube that monitors the functioning of your lungs while they work harder.

How to Prepare for Pulmonary Function Tests

Your healthcare provider will explain the test along with its whole procedure. If you have any questions, you can ask them. They may also direct you to wear comfortable shoes and loose clothing.

For the best results:

  • Avoid smoking before the test. Ask your healthcare provider how long before the test you should stop.
  • Take your prescribed medications before the test unless your healthcare provider directs you not to.
  • If you are on short-acting inhalers, try not to use it for 6-8 hours before the test. If you have to use it, let your healthcare provider know before the test.
  • Don’t consume a large meal at least two hours before the test and don’t drink alcohol at least four hours prior to the test.
  • Don’t perform any hard exercise at least thirty minutes prior to the test.

A pulmonary function test may take anywhere between 15-45 minutes to complete. If you get tired during the test, let your healthcare provider know. It is possible to take breaks at certain points during the test.

After the procedure, you may restart taking any medications your doctor had previously asked you to stop taking. You can also go back to your normal activities, including exercise. If you experienced dizziness or lightheadedness during the test, the doctor will keep an eye on you until your symptoms are relieved and you can safely go home. You will also be informed about when to expect your test results.

Pulmonary function testing is a relatively safe procedure. However, you may experience lightheadedness, dizziness, or tiredness from breathing so deeply. You may also feel tired from exercising or cough from blowing into the mouthpiece. These symptoms should disappear soon after you complete the pulmonary function testing.

The pulmonary function testing procedure can increase your heart rate. You should let your doctor know if you have had a heart attack or any other heart condition recently.

The doctor will compare your test results with the typical scores for your demographic. There is a normal range that is expected for your height, age, and sex.

After you undergo a pulmonary function test, your healthcare provider will contact you in a few days with your results. Contact your provider for the results if you don’t hear from them for a few days. Depending on your diagnosis, you may require regular testing at your future appointments.

Pulmonary function testing enables your doctor to diagnose any conditions affecting the lungs. These tests don’t take a long time and they aren’t painful. So, you should easily get your results within a few days. If you notice any breathing changes, you must seek an appointment with your healthcare provider. They may recommend a pulmonary function test to rule out a lung condition.

The Department of Pulmonary Medicine at Kokilaben Dhirubhai Ambani Hospital, Indore, offers comprehensive diagnostic and therapeutic care for a diverse range of pulmonological diseases. Our services include endoscopic ultrasound, endo bronchial ultrasound, endobronchial brachytherapy, innovative therapeutic techniques, bronchial thermoplasty and surgical interventions like video-assisted thoracoscopic surgery and lung volume reduction. We also offer treatment for sleep disorders, lung cancers, and lung transplantation. Consult the best pulmonologists in Indore who deliver optimum treatment for lung diseases supported by state-of-the-art technology and modern equipment.

We follow an evidence-based approach during all our services to ensure excellent outcomes matching international standards. Apart from having a fully-equipped Bronchoscopy suite with C-arm facilities, we house a state-of-the-art PFT machine. Our focus is on ensuring the speedy recovery of the patient and helping him return to normal activities of daily life as soon as possible.