A blood access device includes (i) a conductive needle configured to pierce a patient's skin and gain access to a blood vessel； (ii) an insulative housing supporting a fluid communication junction between the needle and flexible tube； (iii) a conductor having a first end connected to the insulative housing and a second end extending from the insulative housing in a direction coextensive with the needle such that (a) when the needle has gained access to the blood vessel the patient's skin, the conductor is electrically insulated from the conductive needle and (b) if the needle is pulled so as to interrupt access with the blood vessel, the conductive needle and the conductor come into contact with each other.
