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Body plethysmography
body plethysmography · body box test · lung volume test · plethysmograph
You sit in a clear booth and breathe into a tube. The device precisely measures your lung volume and how air moves through your airways.
When regular spirometry is not enough: to clarify lung disease, before lung surgery, or to track treatment.
⏱ Duration: usually 20 to 40 minutes; the report is usually ready the same day
Be sure to tell your doctor
How to prepare
- Smoking and coffee. Do not smoke for at least a few hours. No coffee or strong tea in the morning.
- Inhalers. Ask your doctor whether to use your inhalers before the test. Do not stop them on your own.
- Food. A light breakfast 2 hours before. Do not eat a big meal.
- Clothing. Loose clothes, with no tight belt.
What to bring
- Your referral
- Your own inhalers
- Past spirometry results
- A list of your medicines
How it goes
- You sit in a clear booth, and the door is closed
- A clip goes on your nose, and you hold the tube with your lips
- First you breathe calmly
- The tube is closed for a second. Keep breathing gently
- Sometimes you are asked to take a deep breath in and breathe out hard
- After a few minutes, the door is opened
What you'll feel
- The booth is closed but clear, and staff talk to you
- When the tube is closed, breathing feels hard. It lasts 1 to 2 seconds
Afterwards
- You can go back to your usual day right away
- The report is usually ready the same day
Common questions
What if I feel scared in the booth?
Say so or wave your hand. The door will be opened right away.
How is it different from spirometry?
Spirometry measures your breath out. Body plethysmography shows the full lung volume, including what is left after breathing out.