PFT with Diffusion Study (DLCO)

The Pulmonary Function Test (PFT) with Diffusion Study, also known as DLCO (Diffusing Capacity of the Lungs for Carbon Monoxide),is a simple and safe breathing test that checks how well the lungs are working—specifically, how well gases like oxygen pass from the lungs into the blood. During the procedure, the individual breathes in a special gas mixture containing nitrogen, oxygen, a very small amount of carbon monoxide (at a harmless level), and a tracer gas. As the gas is inhaled, the lungs absorb some of the carbon monoxide. The individual then exhales into a machine, which measures the amount of carbon monoxide remaining in the breath. This measurement helps determine how efficiently the lungs are transferring gases, helping diagnose lung conditions such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis or emphysema and can also track how well treatments are working.