An advancement mechanism of a lancing device operates to sequentially advance lancets in a cartridge. The advancement mechanism includes a rotary drive gear assembly with a first gear and a second gear that co-rotate in a first angular direction by operation of an inter-gear unidirectional drive mechanism such as a ratcheting mechanism. A second- gear unidirectional lock mechanism, such as a ratcheting mechanism, locks the second drive gear from co-rotating with the first drive gear in a second opposite angular direction without impeding rotation in the first direction. The second gear directly or indirectly rotationally drives a pinion gear, which rotationally drives a cartridge gear to advance the lancets in indexed increments for use. The first drive gear is rotated in the first and second directions by a rack gear of a translating operating handle. In addition, a rotary-gear cap- displacement mechanism and a rotary-gear charging/actuation mechanism are provided in other embodiments.
