The invention relates to an apparatus for extracorporeal blood treatment, comprising a device for detecting a tubing system to be placed in the blood treatment apparatus and a method for detecting a tubing system to be placed in an extracorporeal blood treatment apparatus. The tubing system is detected on the basis of the dependency of the flow rate Q, at which the fluid is delivered by at least one pump of the extracorporeal blood treatment apparatus in a tubing section of the tubing system, on the speed n at which the at least one pump is operated, and on the inner diameter d of the tube of the tubing section. Because the dependency of the flow rate on the pump speed and the tube cross section is known, a conclusion can be drawn as to whether a particular tubing system has been placed in the extracorporeal blood treatment apparatus.