A non-invasive method and system for assessing the survival of a transplanted flap involve the following steps. A control unit instructs a variable-frequency current generator circuit to generate a constant current at a fixed frequency and pass the constant current through a detection electrode. The detection electrode detects a bioelectrical impedance of the skin to which the flap has been transplanted, and the bioelectrical impedance of the skin is compared with a pre-defined threshold value. If the bioelectrical impedance of the skin exceeds the pre-defined threshold value, it is determined that an abnormal condition has occurred.
