A sensor insertion assembly comprising a sensor cartridge having an insertion needle and a sensor within a sterile capsule. The sensor insertion assembly further comprises an inserter comprising a chamber for receiving the sensor cartridge, wherein the inserter further comprises an insertion mechanism operable for actuating the insertion needle for inserting the sensor into a subject. The sensor cartridge is removable from the chamber. The sensor cartridge is operable for shielding the insertion needle upon removal of the sensor cartridge from the chamber.