Disclosed are devices and methods for the control of body fluid flow in the extracorporeal treatment of body fluid. Body fluid flow through on of a body fluid flow circuit (10, 50, 60, 100 or 250) is controlled by alternating applying vacuum pressure and positive pressure to the circuit through a pumping chamber (30, 51, 66, 102, or 200) coordinated with flow control valves (40, 42, 44, 62, 114, 116, 118, and 120) to effect a net downstream flow of body fluid through the circuit.