How is a DLCO test performed?

The DLCO test, or Diffusing Capacity of the Lung for Carbon Monoxide, is specifically designed to assess how effectively gases, particularly carbon monoxide, are transferred from the alveoli in the lungs into the bloodstream. This test specifically measures the diffusion capacity of the lungs, which is crucial for understanding how well oxygen can enter the bloodstream and how efficiently carbon monoxide is absorbed in the lungs.

In performing the DLCO, a patient typically inhales a small amount of carbon monoxide gas and holds their breath for a brief period. The amount of carbon monoxide that diffuses across the alveolar-capillary membrane during this time is measured, allowing healthcare providers to determine the diffusion capacity of the lungs. This is relevant for conditions such as interstitial lung disease, emphysema, or pulmonary edema, where diffusion might be impaired.

The other choices, while they discuss different aspects of pulmonary function tests, do not pertain to the DLCO. For example, measuring lung volume during a forced exhalation relates to dynamic lung volumes and spirometry, whereas residual volume focuses on how much air remains in the lungs after normal exhalation. Measuring respiratory rate over one minute is more a general assessment of breathing rather than a specific evaluation of gas exchange efficiency in the lungs