Diffusing capacity refers to the ability of the lungs to transfer gases, particularly oxygen and carbon dioxide, between the air in the alveoli and the blood in the capillaries. This process is essential for effective respiration and is influenced by factors such as the surface area of the alveoli, the thickness of the alveolar membrane, and the partial pressure of gases. A common test to measure diffusing capacity is the DLCO test, which assesses how well oxygen passes from the lungs into the bloodstream. Abnormal results can indicate various lung conditions, such as pulmonary fibrosis or emphysema, affecting overall respiratory health.