The invention relates to a method for determining or predicting the adequacy parameters that will be achieved at the end of a kidney substitution treatment during said kidney substitution treatment wherein the kidney substitution treatment is provided by a machine, which has an extracorporeal blood system pumping the patient blood at a preset blood flow rate through the blood chamber of a dialyzer, which is divided by a semi-permeable membrane into the blood chamber and a dialyzing fluid chamber and wherein the dialyzing fluid flows at a preset flow rate through the dialyzing fluid system of the machine and collects the waste products from the patient after flowing through the dialyzing fluid chamber of the dialyzer and wherein a device able to measure continuously any kidney substitution treatment related waste product to deliver together with the data provided by the kidney substitution treatment machine a adequacy parameter wherein the device is coupled with the dialyzing fluid system of the kidney substitution treatment machine and wherein the slope of a preferable linear guideline for the adequacy parameter, which end at target adequacy parameter at the end of the kidney substitution treatment, is compared to the slope of the delivered adequacy parameter and if the slope of both are equal with the next delivered adequacy parameters a linearisation is performed to determine or predict the adequacy parameter at the end of the kidney substitution treatment.
