Patent ID: 8041420

Claim:
An apparatus configured to measure the electrical impedance of a tissue sample, wherein the apparatus comprises: (a) an elongate probe having electrodes at one end, wherein the electrodes are configured to transmit an electrical signal between the apparatus and the tissue in contact with the apparatus; and (b) a sheath removably disposed on the elongate probe, the sheath comprising an elongate tubular body having a closed end and an open end and defining an internal cavity, in which the end of the probe on which the electrodes are provided is received within the cavity, and in which at least a portion of the sheath is formed from a material which is capable of providing a conductive path through the sheath between the electrodes and the tissue sample when the sheath is contacted with the tissue sample, and in which the resistivity of the material when the material is contacted with the tissue sample is greater than the resistivity of the tissue sample, and in which the material of the sheath is formed from a polymeric material which has a porous structure such that in use the polymeric material can be impregnated with body fluid to provide an ionically conductive path through the sheath between the electrodes and the tissue sample, and in which the porous material has a pore size effective to block the passage of the polio virus through the porous material, wherein the sheath is removable from the probe after use, such that the probe is configured to be covered with another sheath and used on another patient without requiring sterilization of the probe.