Lung function tests

To treat lung diseases effectively, it is vital to diagnose them at an early stage. Our world-leading experts in respiratory medicine diagnose all types of lung conditions at our state-of-the-art diagnostic facilities for adults and children.

What is a lung function test?

Lung function tests – also referred to as pulmonary function tests – check the efficiency and condition of your lungs. They look at:  

• the total capacity of your lungs 
• the efficiency of your lung in moving oxygen into the bloodstream 
• whether there is any limitation to the airflow 
• whether there is any evidence of inflammation in your lungs 
• whether there is any restriction in your breathing

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 

You 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 experience any of these symptoms persistently, speak to your doctor as soon as possible. You may need 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) 
• respiratory infections 
• suitability to undergo interventional procedures such as bronchoscopy and thoracic surgery

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. 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 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.  

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.  

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. 

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.

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 would typically have to wait up to 24 hours for the results of your lung function test. Results will indicate how well your lungs are working – the form these results take will vary depending on the test taken. If treatment intervention or further tests may be required as a result of the test identifying a long-term condition or disease, your doctor will discuss the next steps with you.

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 £158
• Feno test: From £133
• Methcholine/ Bronchial Challenge: From £420
• Methcholine/ Bronchial Challenge with Feno: From £504
• Blood Gas test: From £155
• Gas Transfer test: From £168
• Plethysmography (Lung Volumes Test): From £187