A system (62, 200, 300, 400, 500, 600, 800, 900, 1000) for administering a medical fluid to an individual comprising: a flexible tube (14, 140, 216, 236, 318, 422, 518, 544, 706); a pumping device (64, 202, 302, 404, 504, 604, 804, 904, 1004); at least two cassettes (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) each comprising a housing (12, 212, 312, 702), wherein the cassettes (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) are designed to be inserted into the pumping device (64, 202, 302, 404, 504, 604, 804, 904, 1004), respectively; a source of medical fluid, wherein the source of medical fluid is fluidly coupled to the cassette (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402); and an occlusion sensor device (506, 508, 608) having infra-red sensors, wherein the first cassette (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) comprises the tube (14, 140, 216, 236, 318, 422, 518, 544, 706) 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 (520, 522) of the tube (14, 140, 216, 236, 318, 422, 518, 544, 706) to prevent a sidewall of the tube (14, 140, 216, 236, 318, 422, 518, 544, 706) located on the same side as the bias bump from expanding past the bias bump so that a sidewall of the tube (518, 544) opposite the bias bump can expand further toward the infra-red sensor (506, 508, 608) than would be possible without the bias bump to increase the sensitivity of the occlusion detection when the first cassette (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) is inserted in the pumping device (64, 202, 302, 404, 504, 604, 804, 904, 1004); and characterised in that the second cassette (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) includes a false reading component (442, 570) for the occlusion sensor device (506, 508, 608) to reflect a sufficient and consistent amount of an emitted signal back to the occlusion sensor device (506, 508, 608) such that the occlusion sensor device (506, 508, 608) detects no change in the intensity of the reflected infra-red signal when the second cassette (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) is inserted in the pumping device (64, 202, 302, 404, 504, 604, 804, 904, 1004). a flexible tube (14, 140, 216, 236, 318, 422, 518, 544, 706); a pumping device (64, 202, 302, 404, 504, 604, 804, 904, 1004); at least two cassettes (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) each comprising a housing (12, 212, 312, 702), wherein the cassettes (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402) are designed to be inserted into the pumping device (64, 202, 302, 404, 504, 604, 804, 904, 1004), respectively; a source of medical fluid, wherein the source of medical fluid is fluidly coupled to the cassette (10, 100, 206, 306, 402, 502, 602, 700, 802, 902, 1002, 1102, 1218, 1302, 1402); and an occlusion sensor device (506, 508, 608) having infra-red sensors,