Analyte testing and monitoring methods, systems, and devices are disclosed. In one aspect, an analyte testing device includes an analyte sensor module configured to hold a sensor cassette structured to store analyte sensors, the analyte sensor module including an opening from which an analyte sensor advances to a testing position to expose at least a portion of the analyte sensor to outside of the analyte testing device； and a lancing module configured to hold a lancet cassette structured to store lancets and project the lancets to outside of the analyte testing device during a blood sample acquisition event to pierce a user's skin.
