PDT 111/D is the device that can be utilized to measure the lung's transfer factor. It is a diffusion capacity test. Completely automatic calibration and self test. The Diffusion capacity test device fully complies with the specifications and requirements of the Single-breath Carbon Monoxide Diffusing Capacity Recommendations for a Standard Technique 1995 Update by American Thoracic Society. Direct gas analysis without gas sampling balloon. It is easily disinfectable patient circuit. It has elevated capacity demand valve with extremely low opening pressure. It has oxygen bounding capacity and the functional residual capacity.