What are lung function tests (lfts)?

LFTs are designed to measure the function of the respiratory system, whose primary aim is to oxygenate the blood. There are four areas which are most important in the process: the chest cavity, the airways, the lung tissue and the pulmonary circulation. If one or more of these areas is not working optimally, the whole system will be affected. We can assess the effectiveness of the whole system and individual aspects by using different LFTs. Nearly all of them require active participation from the person being tested. For example, we can measure the airways that carry air into and out of the lungs by performing Spirometry, the health of the alveolar sacs in the lung tissue by measuring diffusing capacity and the overall function of the system by measuring oxygen saturation.

What are they for?

This depends on the question that your doctor wants to find an answer to. For example, it may be that you are experiencing shortness of breath or wheeze and the doctor thinks it may be Asthma. In another case, you may be undergoing treatment for a condition and lung function tests are performed as a precaution for possible side-effects. There are many possible reasons but LFTs provide a safe and reliable method of helping to diagnose and monitor lung problems.


We test both adults and children. Some require active and co-ordinated interaction to achieve quality results and others are more suited to children who may find the other tests too difficult.

What happens?

This will depend on the testing that your doctor has requested. Once you know this, you can check out the videos on our website to see the details. Also, you can download a sheet that gives you a more detailed description of the tests.

How much do they cost?

This will depend on the test requested. At the time of booking the appointment, we recommend you ask our reception staff for a clear idea of costs associated with your specific test. Concession rates may apply for patients who are Healthcare or Pension card holders.

If you have concerns about your lung health, you can download a request form for your region below. Have a conversation with your doctor about your concerns and give them the request form to complete as they think appropriate.