Pulmonary Function Lab
Diffusion Capacity
What
Lung diffusion testing measures how well the lungs exchanges oxygen and carbon monoxide. This is an important part of lung testing, because the major function of the lungs is to allow oxygen to “diffuse” or pass into the blood from the lungs, and to allow carbon dioxide to “diffuse” from the blood into the lungs.
How
You breathe in (inhale) air containing a very small amount of a tracer gas, such as carbon monoxide. You hold your breath for 10 seconds, then rapidly blow it out (exhale). The exhaled gas is tested to determine how much of the tracer gas was absorbed during the breath.
Details
How to Prepare for the Test
Restrain from eating heavy meal before the test.
Restrain from smoking for at least 4 – 6 hours before the test.
Ask your health care provider whether or not you can use a bronchodilator or inhaler medications the test
How the Test Will Feel
The mouthpiece fits tightly around your mouth. Clips are put on your nose.
Why the Test is Performed
The test is used to diagnose certain lung diseases, and to monitor the status of peopl with established lung disease. Repeatedly measuring the diffusing capacity can help determine whether the disease is improving or getting worse.
