The invention relates to a device for hemodiafiltration with an extracorporeal circulation (10) for receiving blood to be purified and having a hemodialyzer and/or hemofilter (20) which is connected to the blood circulation (10), such that the blood circulation (10) has at least one inlet line (12, 14) for the supply of a replacement fluid upstream and downstream from the hemodialyzer and/or hemofilter (20), characterized in that the apparatus also comprises measurement apparatuses for recording the transmembrane pressure and/or hematocrit (HKT) and/or blood density, such that the measurement apparatuses are connected to a control unit (100) for controlling one or more of the transmembrane pressure and/or the hematocrit (HKT) and/or the blood density, the control unit (100) being constructed so that the control is implemented with the help of at least one of the infusion rates (Qspre, Qspost) of the replacement fluid (13, 15), and the blood to be purified is exposed to a high-frequency electromagnetic field and/or an electric DC field (70) before and/or during contact with the hemodialyzer and/or hemofilter (20).
