A one-time/single use safety lancet system includes a body; a spring coupled to the body; a keeper having a deformable member; and a core for supporting a lancet and having an end coupled to the spring. The core further has a first latch for engaging the deformable member when the lancet system is in an armed state. The deformable member of the keeper is fractured after one use of the lancet system which prevents any subsequent arming of the lancet system. The keeper may be made part of the lancet body. The core may include a second latch, wherein the second latch permanently deforms or fractures the deformable member of the keeper after the single, one-time arming of the safety lancet system.