An apparatus for performing impedance measurements on a subject is described. The apparatus includes at least one electrode and a processing system for: a) determining an encoded value associated with at least one electrode lead and b) causing at least one impedance measurement to be performed using the encoded value. Also described is an apparatus for performing impedance measurements on a subject that includes a processing system for: a) determining an electrode identifier associated with at least one electrode provided on the subject b) determining, using the electrode identifier, an electrode position indicative of the position of the at least one electrode on the subject and c) causing at least one impedance measurement to be performed using the electrode position.
