A system and method for detecting a surgical implement retained within a surgically exposed human body cavity, includes a tag adapted to be attached to a surgical implement insertable within a human body cavity, including a means for receiving an electromagnetic signal and converting it into electric signal; and a means to impress said electric signal on the internal human (or an animal) body where said medical product is used; and means to transmit said electromagnetic signal; and a detecting means including reception means for receiving the electric signal from the body and a detector means connected to the reception means for detecting the electric signal. The envelope of the induced RF wave is demodulated, thus allowing the voltage at the output to vary at a significantly lower frequency. In the event such pulses are sensed, a sensory alert is actuated.