A medical device comprising: a subcutaneous implantable access port (100, 200, 300, 500, 600, 700, 1000, 1100, 1200) having an access port body (101, 201, 601, 701, 1001, 1201) and at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) having a closed removable needle tip (130, 230, 330, 430, 630, 1230) and a needle shaft (128, 228, 328, 428, 628, 1128, 1228) defining a needle lumen (127, 227, 327, 427, 727a, 727b, 1027a, 1027b, 1227); the at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) housed within the access port body (101, 201, 601, 701, 1001, 1201), the at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) extendable and retractable relative to the access port body (101, 201, 601, 701, 1001, 1201); and a needle shift mechanism (122, 222, 322, 622, 722, 1122, 1222) operable such that the at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) is extendable from and retractable into the access port body (101, 201, 601, 701, 1001, 1201) at a plurality of positions of the access port body (101, 201, 601, 701, 1001, 1201); wherein the needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) includes the needle shaft (128, 228, 328, 428, 628, 1128, 1228) for connecting a fluid path with an internal catheter accessing a blood vessel and the closed, removable needle tip (130, 230, 330, 430, 630, 1230) which allows access to the needle lumen (127, 227, 327, 427, 727a, 727b, 1027a, 1027b, 1227) for the passage of fluids; and wherein the needle lumen (127, 227, 327, 427, 727a, 727b, 1027a, 1027b, 1227) is closed by the removable needle tip (130, 230, 330, 430, 630, 1230) when the removable needle tip (130, 230, 330, 430, 630, 1230) is disposed on the needle shaft (128, 228, 328, 428, 628, 1128, 1228). a subcutaneous implantable access port (100, 200, 300, 500, 600, 700, 1000, 1100, 1200) having an access port body (101, 201, 601, 701, 1001, 1201) and at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) having a closed removable needle tip (130, 230, 330, 430, 630, 1230) and a needle shaft (128, 228, 328, 428, 628, 1128, 1228) defining a needle lumen (127, 227, 327, 427, 727a, 727b, 1027a, 1027b, 1227); the at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) housed within the access port body (101, 201, 601, 701, 1001, 1201), the at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) extendable and retractable relative to the access port body (101, 201, 601, 701, 1001, 1201); and a needle shift mechanism (122, 222, 322, 622, 722, 1122, 1222) operable such that the at least one needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) is extendable from and retractable into the access port body (101, 201, 601, 701, 1001, 1201) at a plurality of positions of the access port body (101, 201, 601, 701, 1001, 1201); wherein the needle (126, 226, 326, 426, 526a, 526b, 626, 726a, 726b, 1026a, 1026b, 1126, 1226, 1226a, 1226b) includes the needle shaft (128, 228, 328, 428, 628, 1128, 1228) for connecting a fluid path with an internal catheter accessing a blood vessel and the closed, removable needle tip (130, 230, 330, 430, 630, 1230) which allows access to the needle lumen (127, 227, 327, 427, 727a, 727b, 1027a, 1027b, 1227) for the passage of fluids; and wherein the needle lumen (127, 227, 327, 427, 727a, 727b, 1027a, 1027b, 1227) is closed by the removable needle tip (130, 230, 330, 430, 630, 1230) when the removable needle tip (130, 230, 330, 430, 630, 1230) is disposed on the needle shaft (128, 228, 328, 428, 628, 1128, 1228).