Active surveillance of potential lead anomalies in implanted medical leads utilizes test signal(s) delivered through an output current pathway and induced signals monitored via an independent monitor current pathway to detect for any reactions to the test signals in the induced signals. Various specific responses can be initiated if a potential insulation breach or anomaly in the implanted medical lead is identified due to detection of a “positive” test result in the induced signals on the monitor current pathway in reaction to a test signal applied to the output current pathway.