Tests on the turbine guide row have shown that a meridional contouring of labyrinth sealing chambers above the runner wheels of axial turbomachinery is sensible, if the leakage flow has an angle of twist of about 45 degrees to 90 degrees in relation to the circumferential direction. With increasing twist (angle of twist smaller than 40 degrees), this meridional contouring of the labyrinth sealing chambers becomes more and more ineffective. A semi-empirical calculation equation for the additional losses in the guide wheel caused by leakage flow-above the runner wheel is derived, which shows a good correspondence to experimentally determined values.