The invention refers to a method for determining and adjusting a flow rate of a blood delivery pump (1) of a blood treatment apparatus, the method comprising:- connecting a container (3), which is filled with fluid, with an extracorporeal blood line (5) of the blood treatment apparatus (S1) - performing a priming step to prime the extracorporeal blood line (5) by driving the blood delivery pump (1) at a predetermined theoretical delivery rate to deliver fluid from the container (3) into the extracorporeal blood line (5) (S2) - determining the loss of fluid of the fluid filled container due to delivery of fluid into the extracorporeal blood line (5) during priming (S3) and - determining a correction factor by comparison of a value for an amount of fluid delivered under the theoretical delivery rate with a value for an amount of fluid delivered in real (S4).
