Abstract: The present invention provides a lancet assembly comprising an internal housing, an external housing and a slider unit. The internal housing comprises an internal shaft configured to receive a sharp carrier of the slider unit. The sharp carrier comprises a shoulder that engages a lever arm of the shaft. When the external housing is moved towards the internal housing, an actuator pin in the external housing disengages the shoulder from the lever arm, thereby causing a spring to drive the sharp carrier towards the end of the internal housing. The sharp unit of the sharp carrier then extends through the aperture of the internal housing and pierces the body tissue. A flexible member, coupled to the shoulder, compresses when the sharp unit extends through the aperture. The flexible member thereafter relaxes and retracts the sharp unit back into the internal housing. Furthermore, a catch on the internal housing engages a depression defined in the external housing to prevent the reuse of the lancet assembly.