Carbon Monoxide Diffusing Capacity (Transfer Factor)

Abstract

Pulmonary function tests are designed to measure the mechanical properties of the lung and to evaluate how well the body is performing its respiratory tasks. The carbon monoxide diffusing capacity (DL _CO) test examines the transfer of gases from the alveolar capillary membrane to red blood cell hemoglobin. This paper provides a brief overview of the physiological basis for the test and an introduction to the technical challenges it presents.

DL _CO is frequently used in evaluating obstructive and restrictive lung diseases. It is particularly useful in patients who report dyspnea but have normal spirometry and a normal chest radiograph. It is important to keep in mind that many technical and biological variables can alter DL _CO. Modern instruments are designed to deal with most of these issues and reliable measurements can be obtained in clinical settings with modest effort.

Key Words:

diffusing capacity - DL _CO - transfer factor - gas uptake - variability