The invention relates to a blood treatment device for carrying out an extracorporeal blood treatment in which blood is guided in a blood guidance device having a main blood line and at least one secondary line, the latter being fluidically connected to the main blood line and the main blood line having a dialyzer and, downstream from the dialyzer, a blood treatment element, wherein the blood treatment device has a control device； and a pump configuration, which is equipped for generating blood flows in the main blood line and also in the at least one secondary line, wherein the control device is designed to operate the pump configuration in such a way that a first blood flow rate in the dialyzer is decoupled from a second blood flow rate in the blood treatment element. Furthermore, the invention relates to a blood guidance device for cooperation with the blood treatment device as well as for a blood treatment system.
