Lung function tests

What is a lung function test? 

Lung function tests – also referred to as pulmonary function tests – check the efficiency and condition of your lungs. Our respiratory specialists offer a comprehensive range of lung function tests to diagnose and treat lung diseases quickly and effectively. 

Lung function tests investigate a range of factors including the total capacity of your lungs, the efficiency of your lungs in moving oxygen into the bloodstream, whether your airflow is limited, if your lungs are inflamed, and if your breathing is restricted. The tests can also evaluate the strength of your respiratory muscles. 

Our world-leading experts in respiratory medicine diagnose all types of lung conditions at our state-of-the-art diagnostic facilities for both adults and children. 

Types of lung function test

There are several different types of diagnostic tests for lung conditions – including: 

• a lung volume test 
• spirometry test 
• arterial blood gas analysis 
• a FeNO test 
• an exercise stress test 
• a gas diffusion test 
• a bronchial challenge test 
• forced oscillation technique (FOT) 
• hypoxic challenge test 

You or your child might need a lung function test to:

• investigate the cause of breathing issues 
• diagnose and monitor a lung disease 
• check if a treatment is working 
• assess lung function before a surgical procedure 
• check for lung damage after you’ve been exposed to harmful substances

Signs of poor lung function

Lung function tests are used to investigate common symptoms of poor lung function, including: 

• shortness of breath 
• coughing 
• wheezing 

If you or your child experience any of these symptoms persistently, speak to one of our specialists as soon as possible. You may need to have a lung function test.  

There are several lung conditions that a lung function test can help to diagnose and monitor, including: 

• chronic lung diseases, including airway disease such as asthma, COPD and bronchiectasis 
• chronic unexplained symptoms such as chronic cough and disproportionate breathlessness 
• interstitial lung diseases such as idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, connective tissue disease associated interstitial lung diseases and sarcoidosis (a disease that damages cells around various organs of your body) 
• neuromuscular diseases affecting the lungs 
• respiratory infections 
• suitability to undergo interventional procedures such as bronchoscopy and thoracic surgery 

To find out if you may benefit from a lung function test, speak to our customer services team about booking a consultation with our lung specialists. 

Types of lung function tests 

We offer a range of lung function tests to help diagnose any lung conditions or respiratory diseases. These tests will help identify any problems so you can manage the symptoms effectively. Depending on the results, you may need a blood test or exercise test to help in an accurate diagnosis. 

The lung function tests we offer include: 

Spirometry test 

Spirometry is a test that measures the flow rate and volume of air that your lungs can expel in one breath, and can be carried out in both adults and children. You are seated during the test, and a clip will be placed on your nose to prevent air from escaping. After inhaling fully, you’ll exhale into a small tube which connects to a spirometer (a diagnostic device) as quickly as you can. 

FeNO test 

A fractional exhaled nitric oxide (FeNO) test measures the concentration of nitric oxide when you breathe into a device. Nitric oxide is produced by cells involved in inflammation, associated with asthma, therefore a FeNO result can be used to support a diagnosis or to monitor the effect of treatment. 

This test, which is suitable for children too, is used to identify inflammation in your lungs, helping to diagnose asthma and supporting asthma management. 

Bronchial challenge test 

A bronchial challenge test, also known as an airway provocation test, involves breathing in a small amount of a drug called methacholine that provokes a narrowing reaction in the airways. 

The test helps determine how sensitive your airways are, with people that are more sensitive affected by a much lower dose of the drug. The effect of the drug is quickly reversed once the test is complete via a bronchodilator (inhaler).  

This test is normally performed after other tests, such as spirometry or FeNO, haven’t given a clear result for your doctor but you still have symptoms that can’t be explained. Bronchial challenge tests can be offered to children, but spirometry and FeNO tests are usually sufficient without the need for a bronchial challenge test. 

Arterial blood gas analysis 

Arterial blood gas (ABG) analysis takes a sample of blood from the base of your ear lobe. This diagnostic test shows the levels of oxygen and carbon dioxide in the blood, as well as your blood’s pH level. The sample is taken with a small scalpel, which may cause a little discomfort when the skin is broken.  

An ABG test can be required for the evaluation of respiratory function. It also offers an overview of your body’s metabolic state and is often combined with information obtained from other lung function tests. It is not common for our respiratory specialists to recommend an ABG test to children, but they may suggest it if other tests have not given clear results. 

Gas transfer test 

Gas transfer tests assess how efficient your lungs are at absorbing gases into the bloodstream. A person’s gas transfer can be altered due to many different respiratory conditions, but it can also be useful to assess if someone is fit for surgery or how they react to various treatments. 

You’ll start by breathing normally, before taking one deep breath out. You then take a deep breath in, filling your lungs with a harmless gas and holding it in for approximately 10 seconds, before breathing out into a mouthpiece. An analysis on the gas expired can then detect how efficient your lungs are at exchanging oxygen into your blood. After a short break, you’ll repeat the test to ensure the results match.  

The gas transfer test can help to diagnose and monitor various lung conditions, including COPD and idiopathic pulmonary fibrosis. This test is mainly used for adults and is rarely offered to children. 

Lung volume test 

A lung volume test measures the total amount of air in your lungs, as well as how much air remains after you have breathed out fully. The test requires you to breathe into a device that is similar to a spirometer. You will sit in a small, transparent box that resembles a shower cubicle during the test. A clip will be placed on your nose to stop air from escaping. This test is not commonly recommended to children, but our specialists will let you know if they believe your child would benefit from it. 

Hypoxic challenge test 

A hypoxic challenge test is used to see how well you tolerate the lower oxygen levels that you would experience during a flight. It’s typically recommended if you have a lung condition, certain heart problems, or any issue that might cause low oxygen at altitude.  

During the test, you breathe a controlled gas mixture with reduced oxygen – similar to what you would encounter in an aircraft cabin – while your oxygen saturation and heart rate are monitored. Sometimes blood samples are taken before and after.  

Your clinician may recommend this test when they need to know whether you will require supplemental oxygen during air travel or whether flying could pose a risk for you. 

Forced oscillation technique (FOT) 

If your child is 3-5 years old, they will have a simpler test known as forced oscillation technique (FOT). This test requires active cooperation and is performed with the child seated on the parent’s lap. The test measures how tight the airways are and whether the airways open up after using salbutamol (an inhaler which opens up airways in children with asthma). This test is not widely available, and we are one of only a few centres able to offer a FOT test to young patients. 

To find out what type of lung function test you or your child need, please contact our customer service team, who can help by booking a consultation with one of our specialists.

How long does a lung function test take? 

The timing of each lung function test can vary but are usually around an hour long. Lung function tests are painless and do not require any preparation. As lung function tests are simple and non-invasive, you will be able to return to work or go home straight after. 

Interpreting lung function test results 

You typically will receive the results of your lung function test within 24 hours. Results will indicate how well your lungs are working, and the form that these results take will vary depending on the type of test you had.  

If the test results reveal that you have a long-term condition or disease, and further treatment invention is therefore required, our team will discuss the next steps with you. 

Contact our customer services team to learn more about booking lung function tests with our experienced respiratory team. 

Cost of lung function tests 

The price of your lung function test will vary according to the type of test taken, and whether additional tests are required. Pricing is as follows: 

• Spirometry: From £167
• Feno test: From £140 
• Methcholine/bronchial challenge: From £443 
• Methcholine/bronchial challenge with Feno: From £504 
• Blood gas test: From £164 
• Gas transfer test: From £177 
• Plethysmography (lung volumes test): From £197 

To find out more about booking a lung function test with our respiratory specialists, contact our customer service team.