Full lung function

What is a full lung function test?

This test consists of three different breathing tests:

• spirometry
• gas transfer
• body plethysmography

The tests tell us how you inhale and exhale (breathe in and out), how much air you use and how well your lungs are working. We also measure the total volume of air in your chest by using ‘body plethysmography’. This looks a bit like a telephone box or some children like to call it Doctor Who’s Tardis.

Sometimes we repeat spirometry after you have had some blue inhaler. You might have already performed spirometry at your normal clinic appointment.

What do I have to do?

For all 3 tests you will be asked to:

• breathe normally
• breathe in and out fast
• take big deep breaths
• hold your breath — do not worry, this only lasts a couple of seconds

The body plethysmography test involves the same process, except you are seated in the box. Do not worry — you will be able to open the door if you need to and someone will be talking to you and explaining what you have to do at all times.

How long will the tests take?

Your appointment will last around 45 minutes. Each test only lasts a couple of minutes and you can have as many rests in between as you like.

Do I need to do anything before the appointment?

Your appointment letter will tell you if you need to stop any of your inhalers before the test and for how long. Try not to use the blue inhaler (known as Ventolin, Salbutamol, Salamol, or Bricanyl) for 4 hours before your appointment.