Spirometry

Who is a spirometry for?

Spirometry is suitable for most adults, young people and children aged over 5.  

Our consultants may recommend spirometry to help diagnose a lung condition, or to monitor an existing lung condition and to check how well treatment is working. 

Symptoms that may need investigating with spirometry include:  

• a persistent cough 
• breathlessness 
• wheezing 

We may also recommend spirometry if you’re over 35 and a smoker. 

If you or your child have symptoms of a lung condition that requires a spirometry test, our specialists are happy to help. Contact our customer care team to arrange an appointment.

What does spirometry show?

Spirometry is a practical investigative lung test for diagnosing and monitoring several conditions in adults and children.  

Spirometry can help diagnose and monitor:  

• asthma – which causes inflammation and narrowing of your airways periodically 
• bronchiectasis 
• chronic obstructive pulmonary disease (COPD) – a group of lung conditions that causes your airways to narrow 
• cystic fibrosis – a genetic condition that causes your lungs and digestive system to fill with mucus 
• emphysema – a lung disease caused by damaged air sacs in your lungs 
• post COVID lung disease 
• pulmonary fibrosis and other interstitial lung diseases (ILD) – scarring on your lungs 

The key measures recorded by a spirometer include: 

• forced expiratory volume in 1 second (FEV1): This is how much air you can forcefully breathe out in the first second of a breath. It helps us understand if your airways are blocked or narrowed (known as obstructive lung diseases), such as in conditions like asthma or COPD  
• forced vital capacity (FVC): This is the total amount of air you can forcibly blow out from a position of maximal inspiration (the deepest you can breathe in) to maximal expiration (the most you can breathe out). It is useful for diagnosing and monitoring restrictive lung conditions, where your lungs are stiff or can’t fully expand, such as interstitial lung disease (ILD) 
• FEV1/FVC ratio: This compares how quickly you can breathe air in with the total amount you can breathe out. It helps us understand whether your condition is obstructive (such as asthma or COPD) or restrictive (such as ILD or emphysema)

Sometimes, we may perform a spirometry test before you have surgery to quickly assess your lung function. Doctors also arrange for the test as part of a general health check as you age.     

If you would like a fast and accurate private spirometry test with one of our specialists, please contact our team to arrange an appointment.  

How to prepare for your spirometry

Preparing for a spirometry test is easy as it’s non-invasive.

We may advise adults to stop smoking or vaping for 24 hours beforehand and to avoid alcohol, strenuous exercise and eating large meals a few hours before the test.  

If the test is for your child, it is important that they are not exposed to cigarette smoke or vaping before the test, as this can affect the results. 

Loose-fitting clothing should ideally be worn so that it’s easier to take a deep breath.  

A parent or guardian is usually asked to be present during their child’s test to help reassure and support them while our specialists explain how to breathe into the machine.

How is a spirometry performed?

During a spirometry test, we’ll ask you to breathe into a unique tube attached to a machine (spirometer). 

Before starting the spirometry test, we will measure your height and weight. This information is used to calculate the expected values for your test so that we can compare your results accurately. 

We will ask you to sit down and place a soft clip over your nose to prevent air escaping through it. Next, we will explain what you must do during the test, and we may ask you to practise a few breaths. We’ll begin the spirometry test once you’re happy to proceed.  

We’ll ask you to:  

• close your mouth tightly around the mouthpiece and breathe normally until your breathing is steady 
• take the deepest breath in that you can (maximal inspiration) 
• breathe out as quickly and as forcefully as you can until your lungs are empty (maximal expiration) 
• finally, take another deep breath in (maximal inspiration) to complete the test 

We will ask you to repeat the test a minimum of 3 times to make sure your results are accurate and consistent. If the results vary too much between attempts, we will ask you to repeat the test a few more times until your results are consistent. The maximum number of attempts for adults is 8, while for children it is unlimited.  

Some people may need a repeat test after taking an inhaled bronchodilator medicine (a medication used to manage asthma and COPD). Another test can be beneficial when monitoring your diagnosed condition and seeing if these medicines help manage your symptoms.

How long does a spirometry take?

Spirometry tests can take between 15 and 90 minutes to complete, depending on how many times you need to repeat the test.

Are there any side effects of spirometry?

Generally, spirometry has no side effects as it’s considered a safe test. However, you may feel short of breath or dizzy momentarily after completing it. 

We don’t recommend a spirometry test if you’ve recently had a heart attack or have unstable angina, as it requires physical effort to force out a breath. You will also need to wait at least 2 weeks after eye surgery before having a spirometry test. 

You can go home soon after the spirometry test ends and continue your routine.

Spirometry results 

We’ll send your results to one of our specialists for review. It’s unlikely that we will give you your results immediately afterwards because it’s crucial that our specialists reviews them and provides an accurate diagnosis or follow-up plan. 

We’ll review your results by comparing them to a typical result from someone of the same age, height and sex as you or your child. Then, we can see whether your or their lungs are working correctly.

Obstructive and restrictive spirometry results 

A spirometry test can show if the problems in your lungs are obstructive, restrictive or both.  

In obstructive airway disease, narrowed airways decrease your ability to breathe out, indicating conditions like asthma or COPD.  

Restrictive lung disease reduces the ability of your lungs to fully expand, meaning you can’t breathe in and out as much air as normal. This can occur in conditions such as pulmonary fibrosis or other interstitial lung diseases.

Our team will discuss your results once they’re ready and provide a personalised treatment plan or refer you for further diagnostic tests if necessary.