Abstract: An extracorporeal fluid treatment apparatus which is selectively operable in a disinfecting mode or a treatment mode includes an inlet line, a pre-treatment portion, an input pump, a heater, an input shunt, a filtration device, a post-treatment portion, a drain line and an output shunt. The apparatus also includes a combination of valves which are selectively positionable in disinfecting mode to create an input fluid circuit which includes the pre-treatment portion and the input shunt, and which is in fluid isolation from the post-treatment portion and from the filtration device. In disinfecting mode, the valves are also selectively positionable to create an output fluid circuit which includes the post-treatment portion and the output shunt, and which is in fluid isolation from the pre-treatment portion and from the filtration device.