What is this test?
DLCO (Diffusing Capacity of the Lungs for Carbon Monoxide) evaluates how effectively gases move from the air in the lungs into the bloodstream. It is a measure of gas transfer efficiency.
Why is it done?
DLCO is particularly useful in assessing: interstitial lung disease (ILD) / pulmonary fibrosis, emphysema (even with preserved spirometry), pulmonary vascular disease, unexplained breathlessness, and selected pre-operative assessments.
Who may benefit?
- Patients with suspected interstitial lung disease
- Patients with emphysema
- Unexplained breathlessness
- Monitoring treatment response in ILD
- Pre-operative assessment in selected cases
How is it performed?
You breathe in a mixture of gases, hold your breath for 10 seconds, then breathe out. The exhaled gas is analysed to calculate how much gas has transferred across the lung membrane.
Patient Preparation
Avoid heavy exercise before the test. Do not smoke on the day of testing. Follow instructions about inhalers if advised.
What information does it provide?
A reduced DLCO indicates impaired gas transfer and may suggest ILD, emphysema or pulmonary vascular disease. The degree of reduction helps assess severity and monitor disease progression.
