PFT/Lung Function Tests
A series of tests will be performed to determine how well you lung functions. The testing may take from 5 to 30 minutes, depending upon how many tests are done.
Several different types of tests can provide information about lung function
Spirometry. Spirometry measures how quickly your lungs can move air in and out. It can also measure how much air your lungs move in and out. To be tested, you breathe into the mouthpiece of a long, flexible tube attached to a recording device (spirometer).
Gas dilution tests. Gas dilution tests measure the amount of air that remains in your lungs after you exhale as completely as possible (residual volume). To be tested, you breathe a known amount of a gas (either 100% oxygen or a certain amount of helium in air) from a container.
Carbon monoxide diffusing capacity. Diffusing capacity for carbon monoxide (also called transfer factor, or TF) measures how well your lungs transfer a small amount of carbon monoxide (CO) gas into the blood. Two different techniques are used for this test. If the single-breath or breath-holding technique is used, you will take a breath of air containing a very small amount of carbon monoxide from a container while measurements are taken. In the steady-state technique, you will breathe air containing a very small amount of carbon monoxide from a container. The amount of carbon monoxide in your arterial blood will then measured.
Arterial blood gases. Arterial blood gases determine the amount of oxygen and carbon dioxide in your bloodstream.
You may feel some pain from the needle used to collect the blood. The other lung function tests are usually painless. Some of the tests may be tiring. Ask the doctor what medicines to take or withhold before the test. Also, it is best to have as little to eat as possible before the test.