What is lung function testing ?

Lung function testing, also known as respiratory or pulmonary function tests are diagnostic medical tests that are performed to assess how well your lungs and airways are working. These tests are routinely performed in patients who experience any sort of respiratory symptoms including cough, shortness of breath or chest tightness. Your doctor may also request these tests if you’re a current or ex-smoker or if you’ve been exposed to other agents such as dust, chemicals or smoke which are known to potentially cause lung disease. They are often  performed before commencing or during employment if you work in a role where you may encounter dust, chemicals or other industrial exposures. This includes recreational activities such as scuba diving as breathing compressed gas can be dangerous if you have asthma.  If you have a suspected or known lung disease you will likely do these tests routinely to monitor progression, or for your doctor to monitor response to treatment.

Is there any preparation ? 

You should avoid taking inhaled medications (puffers) for 24-48 hours before testing. If you have Ventolin you can take this up 6 hrs prior to testing.

If you become too breathless to continue withholding your inhalers then take Ventolin or your other prescribed medications as usual and let our scientist know at the time of testing. You should continue to talk all other non-breathing related medications as usual.

You should also avoid large meals, strenuous exercise and smoking prior to testing.

We won’t be asking you to run or do any exercise so you can wear normal clothes, as long as they’re not too tightly fitting

How long will it take ? 

Testing takes around 20 minutes on average. Depending on the tests requested it may be a few minutes more or longer.

Who will perform these tests ? 

The testing will be completed by a trained respiratory function scientist, reviewed by our chief respiratory physiologist and then a written report generated by a respiratory physician will be returned to your referring doctor.

What is Spirometry ? 

Spirometry is the simplest form of lung function testing. It is a basic test that measures the maximum amount of air that you can blow out from your lungs, and how quickly. In some conditions you may have a reduced lung capacity, though most commonly we observe narrowing of the airways that causes reduced flow rates. This may be due to asthma, COPD or other similar conditions. You will be asked to blow out as fast and as hard as you possibly can. Maximum effort is essential for an accurate result. We will repeat the test multiple times to ensure best results and then give you Ventolin to see if it helps you breathe more easily.

What is FeNO ? 

FeNO stands for fraction of exhaled nitric oxide. It is an exhaled breath test similar to a police breathalizer only it measures the concentration of biomarkers in your airways. It tells us if your airways are inflamed, and if you’re likely to be responsive to inhaled steroids. Inhaled steroids are one of the most frequently prescribed medicines used to treat asthma and this test can help your doctor prescribe or fine tune appropriate treatment. It is also useful for identifying underlying inflammation even when your spirometry is normal.

What are diffusion capacity tests? 

Spirometry tells us physically how much air we can get into our lungs and how easily, diffusion capacity testing tells us about how well the lungs can absorb oxygen from the air and deliver it to the blood. Low diffusion capacity can often result in a feeling of breathlessness, even if you lung capacity and airways are fairly normal. It is a sensitive test that can pick up early lung damage from smoking even before other tests start to appear abnormal.

You will be asked to blow all the way out, then inhale a test gas and hold your breath for 10 seconds.

What are lung volumes tests ? 

Not all the air in our lungs is able to be exhaled, which makes our true lung capacity difficult to measure with simple tests. The lung volumes tests involves sitting in a glass chamber (similar to an old phone box). In different lung conditions air can become trapped in the chest which can contribute to the feeling of breathlessness, and this test helps assess this. It also tells us if the lung capacity is smaller than it should be, which is often the case in fibrosis or occupational lung diseases.

What is a challenge test ? 

A bronchial challenge test is used to assess asthma and works by irritating the airways to provoke a response. One of the defining characteristics of asthma is variability in symptoms – one minute you might be totally fine and the next you have trouble breathing. If you’re having a good day or no breathing difficulty at the time of simple spirometry testing we may not show any abnormality. The challenge test is designed to irritate the airways, causing minor dehydration which mimics heavy breathing during exercise. In asthmatics this generally results in minor spasms or constriction of the muscles in the airways and we can measure these changes in the flow rates as you’re breathing. The test involves inhaling a series of fine powder capsules. It may make you cough but it’s otherwise safe and we’ll make sure the effects (if any) are reversed within minutes of the test being completed. Most people leave breathing better than when they came in.