Spirometry is probably the most well-known of the pulmonary function tests (PFT). This is the test where we ask you to “keep blowing, keep blowing!” There is another test that can provide a wealth of information on how the lungs are actually exchanging the gases that keep us alive known as the diffusion capacity of lung for carbon monoxide or DLCO.
DLCO assesses how efficiently oxygen moves from your lungs to your blood. It’s a type of pulmonary function test that helps healthcare providers understand lung function. During the test, you inhale a gas mixture containing a small amount of carbon monoxide, measuring how much transfers to your blood.
What should I expect during a lung diffusion (DLCO) test?
During a DLCO test, a technician will put a clip over your nose or a mask on your face. They’ll have you:
- Put your mouth over a mouthpiece attached to a machine. The machine will deliver the gas mix. It will also measure and record your results throughout the test.
- Take a few normal, steady breaths.
- Inhale deeply and exhale completely.
- Breathe in quickly through your mouth.
- Hold your breath for 10 seconds or as long as you can.
- Breathe out.
Your technician may wait a few minutes and repeat the test at least one more time.
What does low DLCO mean?
Low DLCO means your lungs aren’t getting oxygen from the air to your blood efficiently.
Common conditions include:
- Anemia – you have lack of hemoglobin to pick up the CO, so uptake is reduced.
- Emphysema & COPD – The surface area has decreased due to thin and collapsible alveoli, so CO uptake is reduced
- Pulmonary Fibrosis – The alveolar membrane is scarred and thick, so CO update is reduced
What does high DLCO mean?
Some conditions include:
- Obesity.
- Asthma.
- Bleeding in your lungs.
- Cardiac shunt.
- Heart failure.
