Cassettes and methods of using same

A system for administering a medical fluid to an individual comprising:

• a flexible tube;
• a pumping device;
• at least two cassettes each comprising a housing, wherein the cassettes are designed to be inserted into the pumping device, respectively;
• a source of medical fluid, wherein the source of medical fluid is fluidly coupled to the cassette;
• and
• an occlusion sensor device having infra-red sensors, wherein the first cassette comprises the tube comprising a material selected from the group consisting of opaque, infra-red reflective, and combinations thereof, and a bias bump located adjacent to a portion of the tube to prevent a sidewall of the tube located on the same side as the bias bump from expanding past the bias bump so that a sidewall of the tube opposite the bias bump can expand further toward the infra-red sensor than would be possible without the bias bump to increase the sensitivity of the occlusion detection when the first cassette is inserted in the pumping device;
• wherein the second cassette includes a false reading component for the occlusion sensor device to reflect a sufficient and consistent amount of an emitted signal back to the occlusion sensor device such that the occlusion sensor device detects no change in the intensity of the reflected infra-red signal when the second cassette is inserted in the pumping device.