A method of measuring Sub-Epidermal Moisture (SEM) as a means to detect and monitor the formation of pressure ulcers. The device used in this method incorporates an array of electrodes which are excited to measure and scan SEM in a programmable and multiplexed manner by a battery-less RF-powered chip. The scanning operation is initiated by an interrogator which excites a coil embedded in the apparatus and provides the needed energy burst to support the scanning/reading operation. Each electrode measures the equivalent sub-epidermal capacitance corresponding and representing the moisture content.
