This disclosure relates to medical fluid delivery sets and related systems and methods. In some aspects of the invention, a medical fluid cassette includes a plunger slidably disposed within a recess of a base of the cassette such that a substantially liquid-tight seal is maintained between the plunger and the base as the plunger slides axially within the recess. The plunger and the base cooperate to at least partially define a fluid pump chamber. When the plunger is displaced in a first direction, fluid is forced out of the fluid pump chamber, and when the plunger is displaced in a second direction, fluid is drawn into the fluid pump chamber.
