An access disconnection system is described. The system comprises: an extracorporeal circuit first and second contacts provided in the extracorporeal circuit a current source communicating with at least one of the first and second contacts and configured to generate a current within fluid flowing through the extracorporeal circuit and an apparatus positioned to apply a signal at multiple points along a path in parallel to the extracorporeal circuit, the signals tending to prevent at least a portion of the current from travelling through the parallel path.
