1. A device for extracorporeal blood purification, comprising a dialyzer (10), divided into a first and second chamber by a semipermeable membrane (11), the first chamber (12) located in the path of the dialysis solution and the second chamber (13) made with the possibility of connection to the patient’s circulatory system (1) using a blood inlet tube (14) and a blood outlet tube (15), - a fresh dialysis fluid supply line (20), - a drain line (30) for spent dialysis fluid, - a measuring device (40), located in the drain line (3 0) for evaluating the absorption of spent dialysis fluid flowing along the drain line (30), the measuring device (40) comprising at least one radiation source (41) of substantially monochromatic electromagnetic radiation, as well as a detection system (42) for determining the intensity of electromagnetic radiation, characterized in that means (50) are provided for compensating for changes that occur in the intensity of the electromagnetic radiation of the radiation source (41) and / or the sensitivity of the detector system (4 2) .2. The device according to claim 1, characterized in that the temperature controller (51) is provided as a means (50) for adjusting the temperature of the radiation source (41) to a predetermined operating temperature Ti and / or the temperature of the detection system (42) to a predetermined operating temperature T .3. The device according to claim 1, characterized in that the electronic controller (52) is provided as a means (50) for regulating the intensity I of the electromagnetic radiation of the radiation source (41) in such a way as to enable the determination of1. Устройство для экстракорпоральной очистки крови, содержащее- диализатор (10), разделенный на первую и вторую камеры полупроницаемой мембраной (11), при этом первая камера (12) расположена в пути диализирующего раствора и вторая камера (13) выполнена с возможностью подсоединения к системе кровообращения пациента (1) с помощью трубки (14) впуска кров
