A system and method for detecting skin penetration. The system comprises an invasive component for penetrating the skin a dummy electrode for making contact with the surface of the skin at least one penetrating electrode disposed in the invasive component and a Wheatstone bridge circuit wherein a resistance across the dummy electrode and the penetrating electrode constitutes one of the resistive legs of the Wheatstone bridge circuit and skin penetration of the invasive component is detected based on a differential output voltage from the Wheatstone bridge circuit.
