Abstract: An extracorporeal blood processing system comprises a plastic molded compact manifold that supports a plurality of molded blood and dialysate fluidic pathways along with a plurality of relevant sensors, valves and pumps. A disposable dialyzer is connected to the molded manifold to complete the blood circuit of the system. The compact manifold is also disposable in one embodiment and can be detachably installed in the dialysis machine. Two-way valves in the manifold are used to direct the dialysate flow to the dialyzer in hemodialysis mode of operation and to bypass the dialyzer to direct the flow of infusion grade dialysate directly to the patient in hemofiltration mode of operation.