Lung plethysmography

You will sit in a large airtight cabin known as a body box. The walls of the cabin are clear so that you and the health care provider can see each other. You will breathe or pant against a mouthpiece. Clips will be put on your nose to close off your nostrils. Depending on the information your doctor is looking for,…

Let your doctor know if you are taking any medicines, particularly ones for breathing problems. You may have to temporarily stop taking certain medicines before the test. Wear loose clothes that allow you to breathe comfortably. Avoid smoking and heavy exercise for 6 hours before the test. Avoid heavy meals before the…

The test involves rapid and normal breathing, and should not be painful. You may feel short of breath or lightheaded. You will be monitored at all times by a technician. The mouthpiece may feel uncomfortable against your mouth. If you have trouble in tight spaces, the box might make you anxious. But it is clear and…

The test is done to see how much air you can hold in your lungs during rest. It helps your doctor determine if a lung problem is due to damage to the lung structure, or a loss of the lungs' ability to expand (get bigger as air flows in). Although this test is the most accurate way to measure how much air you can hold…

Normal results depend on your age, height, weight, and sex.

Abnormal results point to a problem in the lungs. This problem can be due to a breakdown of the lung structure, a problem with the chest wall and its muscles, or a problem with the lungs being able to expand and contract. Lung plethysmography will not find the cause of the problem. But it helps the doctor narrow down…

Risks of this test may include feeling: Anxiety from being in the closed box Dizzy Lightheaded Short of breath

Bhakta NR, Kaminsky DA. Pulmonary function testing: physiologic and technical principles. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 7th ed. Philadelphia, PA: Elsevier; 2022:chap 25. Chernecky CC, Berger BJ. Pulmonary function tests (PFT) - diagnostic. In:…