Lung Function Test

Lung function test

Similar to how blood tests are used to see how well our body is functioning, there are also tests to see how well each individual organ is functioning. 

What are Lung Function tests?

Lung function tests, also known as pulmonary function tests in Singapore, are used to determine how well our lungs are functioning. These tests are able to show how much air is inhaled and exhaled, how much air travels from your lungs to your blood, and how your lungs respond to exercise. 

There are a few types of lung function tests, these are:

  • Spirometry: measures how much air is inhaled and exhaled. It can also show how quickly you can empty your lungs.
  • Body plethysmography or lung volumes: measures how much air is in your lungs when you inhale and how much air stays in your lungs when you exhale. 
  • Lung diffusion capacity or gas diffusion study: measures how well oxygen moves from your lungs into your blood.
  • Cardiopulmonary exercise test (CPET): measures how your lungs, heart, and muscles respond to exercise.
  • Pulse oximeter: a probe is attached to your finger to check the level of oxygen within your blood.
  • Arterial blood gas test: measures the levels of oxygen and carbon dioxide in your arterial blood.
  • Exhaled nitric oxide test: measures the level of nitric oxide gas in your body.
Illustration of Pulmonary Function Test

How do Lung Function tests work?

Most of the time, lung function tests are performed in an out-patient setting. You must wear loose and comfortable clothing. Loosen your jewelry as they might restrict your breathing or cause problems with the test. In general, most lung function tests are carried out in the following way:

  • A soft clip will be placed over your nose. This ensures that all your breathing (inhaling and exhaling) goes through your mouth and not your nose.
  • A tube-like device with a sterile mouthpiece attached, is placed into your mouth and you are to inhale and exhale into it. 
  • As you are breathing, your results are being interpreted by a computer.
  • You must repeat the tests several times to ensure that the results are accurate.

Any test that pertains to exercise will involve a treadmill or an exercise bike. You will be attached to a heart rate monitor and blood pressure machine during the test to ensure that your vital signs are normal. 

What happens after a Lung Function test?

Lung function tests are non-invasive, this means you will be able to return to your normal activities immediately. However, if you have a history of lung conditions, you may feel a little tired after the tests. Once your respiratory specialist has anaylsed your results, he/she will discuss them with you and decide what the next steps are.

Who needs a Lung Function test?

Lung function tests can be done for a number of reasons in both healthy individuals and individuals with lung conditions, these reasons include:

  • Part of a routine physical test: check how well the lungs are functioning
  • Allergies: analyse how allergies affect lung function
  • Lung conditions: such as bronchiectasis, asthma, sarcoidosis, chronic bronchitis, asbestosis, tuberculosis, pneumonia, etc., and how they affect lung function
  • Diagnosis: for individuals with chest pains, breathlessness, chronic cough, etc. 

Lung function tests are also used prior to surgery for individuals with heart, lung, or other conditions and smokers. 

How do I prepare for a Lung Function test in Singapore?

Before a lung function test, you must:

  • Inform your doctor about any medications or supplements you are taking
  • Stop smoking a few hours prior
  • Not eat a heavy meal
  • Wear comfortable, non-restrictive clothes
  • Avoid caffeine 

What are the benefits of a Lung Function test?

  • Understand how well your lungs are functioning
  • Non-invasive
  • Short procedure
  • No downtime
  • Helps your doctor diagnose and decide on treatment if necessary

What are the common risks or complications of a Lung Function test in Singapore?

There are minimal to no risks or complications involved in a lung function test, however, like all medical procedures, a small number of individuals might experience some complications or risks. These are:

  • Dizziness due to exertion 
  • Breathlessness or shortness of breath
  • Coughing
  • Asthma attack
  • Increased heart rate
  • Pneumothorax

Individuals with the following, are not advised to have a lung function test:

  • Recent eye surgery
  • Recent chest or abdominal surgery
  • Chest pains due to heart attack or surgery
  • Active tuberculosis or respiratory infection such as a flu

How well you tolerate a lung function test, depends on your general health. Please inform your doctor if you have any of the above factors.

Frequently asked questions

What does normal lung function results look like?

Typical lung volume is different for everyone, it is affected by age, gender, height, and even ethnicity. But a typical range would be between 80% to 120% of the predicted.

WALK IN Mount Elizabeth Medical Centre, 3 Mount Elizabeth, #12-03, Singapore 228510
© Copyright 2023. All rights reserved | Interventional Pulmonology & Lung Clinic