The results of Single-Breath-Test with carbon monoxide offers only a rough estimation of the gas exchange situation in the lung as concerns pulmonary diffusion capacity. This statement is related to overestimation of diffusion capacity and reduced possibility to characterize disturbances of pulmonary diffusion function on the basis of values assessed. The proposed six-array-diagram offers the possibility to characterize the disturbances of diffusion more exactly and to differentiate them simultaneously regarding the values determined. So it is possible, to characterize better structural changes of the blood-gas barrier of the lung and to demonstrate compensatory mechanisms.