Diffusing Capacity

Diffusing Capacity (DLCO)

This is an easy test to perform in conjunction with spirometry, taking only a few extra minutes and involving minimal discomfort for the patient.

What is the purpose of a
DLCO test?

It is an extremely useful test of how gas diffuses into the lungs. This testing aids in the diagnosis of various respiratory conditions, but is specifically ideal for the identification and monitoring of emphysema. The DLCO is low in COPD, but normal in asthma. It is also low in interstitial lung disease, anaemia and pulmonary vascular disease.

How is a DLCO test performed?

Carbon monoxide – a gas that has a high affinity for haemoglobin (a protein in red blood cells that carries oxygen) – is used in diffusing capacity testing. During the assessment, the patient breathes in a small amount of a gas mixture containing this carbon monoxide and holds their breath for 10 seconds. Through evaluating the exhaled air, the amount of carbon monoxide exhaled is measured, and thus the amount absorbed into the bloodstream is determined. This test is ideal for patients who struggle to perform the breathing exercises required in spirometry. 

Do I need a DLCO?

DLCO tests may be conducted at a respiratory clinic for patients with ranging lung disease symptoms. GPs should refer patients for a DLCO if they have a persistent, mucus-producing cough, experience shortness of breath with exercise, feel chest tightness, or unintentionally squeak or whistle when breathing. 

Contact us to book an appointment

Visit us at either our Clayfield or North Lakes location and experience compassionate care in a comfortable environment, tailored to meet your unique needs.