Full Lung Function Test 

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What is this information about?

This information is for patients who are attending a Full Lung Function Test. The test provides detailed and accurate information about your breathing. It helps your doctor decide on the most appropriate treatment, if needed. 

What does the Full Lung Function Test involve?

You will be asked to blow into tubes using a mouthpiece while wearing a nose peg. The mouthpiece is connected to specialised equipment. 

We may have to repeat the test three or four times to achieve a consistent result. 

The test is made up of three different breathing assessments: 

Spirometry

This measures how much air you can breathe out and how fast. You’ll begin by breathing normally, then take a deep breath in and blow out as hard and fast as you can. When your lungs are empty, you will take a quick, deep breath back in. 

Gas Transfer

This checks how well oxygen and carbon dioxide move between your lungs and blood. We will ask you to breathe out fully, take a deep breath in, and then hold your breath for up to 10 seconds, before blowing all the way out.

Static Lung Volumes

This measures the total size of your lungs. You’ll breathe in and out gently and normally. When asked, you’ll take a deep breath in, then breathe out slowly and fully. 

How should I prepare for the test?

Follow these instructions before your appointment: 

• Do not smoke or vape for 24 hours before your test. 

• Avoid alcohol and heavy meals for at least 4 hours before. 

• Do not consume caffeine for at least 4 hours before. 

• Avoid vigorous exercise for at least 30 minutes. 

• Do not use short-acting inhalers (for example, Ventolin or Bricanyl) unless your nurse or doctor tells you otherwise 

Will the test cause any harm?

The tests can feel tiring, but you we will give you time to rest between each one. There are no known risks or side effects.

How long will it take?

The full testing procedure usually takes between 30 minutes and 1 hour. 

What should I wear?

Please wear your normal, comfortable clothing. 

What happens to the results?

The physiologist will write a report and will send it to your consultant.  

The consultant will review the results along with your symptoms and medical history. 

Please contact the department before your testing appointment if you:

• Have a current chest infection requiring antibiotics 

• Have had any surgery in the past two months 

• Are feeling unwell on the day of the test