Pulmonary function tests are painless and are usually performed in your doctor’s office or in a laboratory.
For breathing tests, your doctor or a technician will place soft clips on your nose, and you will breathe into a tube. You will be asked to breathe in different ways so that different lung functions can be measured.
For body plethysmography, you will be seated in a glass booth, and will breathe through a tube attached to a testing machine. The pressure inside the booth is measured to show how much air you can breathe into your lungs.
For lung diffusion capacity tests, you will breathe in a gas through a tube, hold your breath for 10 seconds, and then blow it out rapidly.
Pulse oximetry uses a sensor containing a special light to measure the amount of oxygen in the blood. The sensor is attached to your finger.
Arterial blood gas tests involve drawing a blood sample and examining it to determine how much oxygen is in the blood.
Exercise tests are usually performed using a treadmill or stationary bicycle. Your doctor will ask you to walk or pedal for different amounts of time and at different intensities depending on what tests are being performed. Some exercise tests require only mild exertion, while others require that you exercise as hard as you can.