A medical device comprising a subcutaneous access port having an access port body and at least one needle having a removable needle tip and a needle shaft defining a needle lumen; the at least one needle housed within the access port body, the at least one needle extendable and retractable relative to the access port body; and a needle shift mechanism operable such that the at least one needle is extendable from and retractable into the access port body at a plurality of positions of the access port body.