Carbon Monoxide Diffusing Capacity Testing

Also known as: DLCO testing, transfer factor for carbon monoxide, TLCO, lung diffusion testing.

What is carbon monoxide diffusing capacity testing?

Carbon monoxide diffusing capacity testing measures how well the lungs exchange oxygen and carbon dioxide. It’s useful for diagnosing a variety of different breathing problems.


What happens during the procedure?

The patient has a clip placed on the nose, and inhales air that contains carbon monoxide and a tracer gas through a mouthpiece. After holding their breath for 10 seconds, the patient exhales into the mouthpiece. The amount of absorbed tracer gas is measured.


Is any special preparation needed? 

The patient may need to avoid smoking, certain medications, and eating heavily before the test.

What are the risk factors?

There are no major risk factors to carbon monoxide diffusing capacity testing.

Reviewed by: Antonio Rodriguez, MD

This page was last updated on: January 18, 2022 06:59 PM