A device for delivery of an agent or the removal of body fluid, comprising: a housing; a controllable driver positioned in the housing; a penetrating member (412, 902) configured to be coupled to the controllable driver and positioned in the housing; a feedback loop coupled to the controllable driver to provide for a controlled delivery of the penetrating member for the delivery of an agent to or removal of body fluid from a selected site of the body; a processor supporting the feedback loop and coupled to a controllable drive force generator to signal or actuate the controllable drive force generator to drive the penetrating member at various velocities; (i) a reservoir to contain the agent to be delivered coupled to the penetrating member for delivery of the agent; or (ii) a body fluid capture structure coupled to the penetrating member for withdrawal of body fluid; and characterised by further comprising a finger positioning system configured to provide feedback to a user that the user's finger is in a correct position for a test, wherein the finger positioning system comprises: a capacitance sensor including an electrified plate sensing surface; and driver electronics including a driver integrated circuit, wherein the driver electronics is coupled to the capacitance sensor and is configured to determine a finger position by continually changing a voltage applied to the electrified plate sensing surface and determining a capacitance between the user's finger and the capacitance sensor by measuring an amount of current required to change the voltage applied to the electrified plate sensing surface. a housing; a controllable driver positioned in the housing; a penetrating member (412, 902) configured to be coupled to the controllable driver and positioned in the housing; a feedback loop coupled to the controllable driver to provide for a controlled delivery of the penetrating member for the delivery of an agent to or removal of body fluid from a selected site of the body; a processor supporting the feedback loop and coupled to a controllable drive force generator to signal or actuate the controllable drive force generator to drive the penetrating member at various velocities; (i) a reservoir to contain the agent to be delivered coupled to the penetrating member for delivery of the agent; or (ii) a body fluid capture structure coupled to the penetrating member for withdrawal of body fluid; and (i) a reservoir to contain the agent to be delivered coupled to the penetrating member for delivery of the agent; or (ii) a body fluid capture structure coupled to the penetrating member for withdrawal of body fluid; and characterised by further comprising a finger positioning system configured to provide feedback to a user that the user's finger is in a correct position for a test, wherein the finger positioning system comprises: a capacitance sensor including an electrified plate sensing surface; and driver electronics including a driver integrated circuit, a capacitance sensor including an electrified plate sensing surface; and driver electronics including a driver integrated circuit, wherein the driver electronics is coupled to the capacitance sensor and is configured to determine a finger position by continually changing a voltage applied to the electrified plate sensing surface and determining a capacitance between the user's finger and the capacitance sensor by measuring an amount of current required to change the voltage applied to the electrified plate sensing surface.