What is the name of the measurement used to assess the transfer of gas from the alveoli to the blood?

The measurement used to assess the transfer of gas from the alveoli to the blood is known as diffusion capacity. This concept refers specifically to how effectively gases like oxygen and carbon dioxide can move across the alveolar membrane into the bloodstream. In respiratory therapy and pulmonary function testing, diffusion capacity is often evaluated using tests such as the DLCO (Diffusing Capacity of the Lung for Carbon Monoxide), which measures how well carbon monoxide, a surrogate for oxygen, can be transferred from the alveoli to hemoglobin in the blood.

This is an important parameter for diagnosing and managing various pulmonary conditions, as decreased diffusion capacity can indicate issues such as emphysema, pulmonary fibrosis, or other disorders that impair gas exchange. Other options like oxygen saturation represent the amount of hemoglobin bound with oxygen in the blood, while vital capacity and tidal volume refer to lung volumes rather than the specific ability of gas transfer at the alveolar level. Thus, diffusion capacity directly addresses the question of gas exchange efficiency.