An apparatus for detecting a surgical implement in human or animal tissue comprises a battery powered marker. The marker (20) is secured to the surgical implement (16) and positioned within a surgical wound (12). A detection means (30) has an antenna (32) disposed in close proximity of the tissue (2). Means are provided for capacitance coupling of both the marker and the antenna to the tissue. A signal generating means (22) generates a signal having a predetermined frequency band ranging from about 10MHz to 1GHz. The signal generated by the signal generating means causes a field generating means (27) to generate an electromagnetic field providing the marker with signal identity.
