Patent ID: 7973667

Claim:
A method of detecting a liquid leak in an extra corporeal blood treatment system comprising: attaching a wetness sensor to an absorbent material surrounding a needle insertion site, the wetness sensor including: a solid support comprised of a non-electrically conductive material having first and second surfaces, an electronic transmitter attached to said first surface of said solid support, a trace antenna coupled to said electronic transmitter printed on said first surface of said solid support, an electric circuit printed on said second surface of said solid support for detecting the presence of wetness, a microcontroller in communication with said electronic transmitter and said electric circuit, a power source connected to said microcontroller, electronic transmitter and electric circuit, and a voltage detection device coupled to said power source and in communication with said microcontroller for detecting a low power supply of said power source; whereby the wetness sensor detects an electrical signal, determines whether the signal is greater than a predetermined wetness detection threshold value, wherein a wetness detection threshold value greater than the predetermined value indicates the presence of wetness, and directs the electronic transmitter to transmit to a receiver unit in communication with the wetness sensor at least one signal that wetness has been detected, whereby the receiver unit triggers an alert system, comprised of one or more alarms selected from the group consisting of the display of a warning message, an audible alarm, a visual alarm and a physical alert, and directs the extracorporeal blood treatment system to stop one or more pumps or close one or more blood line valves of the system.