Apparatus for use in performing impedance measurements on a subject, the apparatus including a probe having a plurality of electrodes, the probe being configured to allow at least some of the electrodes to be in contact with at least part of the subject and a processing system for, determining at least one first impedance value, measured at a site using a first electrode configuration, determining at least one second impedance value, measured at the site using a second electrode configuration and determining an indicator indicative of the presence, absence or degree of an anomaly using the first and second impedance values.
