A test-sensor cartridge comprising a plurality of test sensors adapted to assist in determining an analyte concentration of a fluid sample. The cartridge further comprises a plurality of walls forming a cavity therein. The cavity is adapted to include the plurality of test sensors. At least one of the plurality of walls forms at least one aperture. The cartridge further comprises a lid adapted to enclose the cavity. The cartridge further comprises a locking feature adapted to lock the lid to one or more of the walls. The locking feature is adapted to be disengaged by the at least one aperture receiving a projection of an analyte-testing instrument.