A medical device (110) for detecting at least one analyte in a body fluid, a method of using a medical device (110) and a method for assembling a medical device are disclosed. The medical device (110) comprises:- at least one analyte sensor (122) having an insertable portion (160) adapted for at least partially being inserted into a body tissue (194) of a user,- at least one electronics unit (172), wherein the analyte sensor (122) is operably connected to the electronics unit (172), wherein the electronics unit (172) comprises at least one interconnect device (174) with at least one electronic component attached thereto；- at least one insertion cannula (114), wherein the analyte sensor (122) partially is placed inside the insertion cannula (114)；- wherein the insertion cannula (114) is movable in between at least one extended position (224) and at least one retracted position (222), wherein the electronics unit (172) remains in a fixed position (225) when the insertion cannula (114) is moved from the extended position (224) to the retracted position (222) or vice versa；- wherein the analyte sensor (122) comprises at least one active portion (148) having at least one sensor electrode (208) for sensing the analyte thereon；- wherein the analyte sensor (122) further comprises at least one passive portion (152) electrically connected to the electronics unit (172) in at least one connector portion (206)；- wherein the passive portion (152) provides, in between the connector portion (206) and the active portion (148), at least one reserve loop (150) configured for compensating for an insertion path during movement from the retracted position (222) into the extended position (224) or vice versa.
