A transcutaneous analyte sensor assembly comprises: a housing adapted for mounting on a skin of a host； an electronics unit configured to releasably mate with the housing； and a sensor configured to measure a level of an analyte in the host, wherein the sensor is operably connected to the electronics unit when the electronics unit is mated to the housing. The housing comprises at least two electrical contacts configured to operably connect the sensor to the electronics unit when releasably mated thereto. The electrical contacts are coaxially aligned with the sensor.
