A sensor patch, system, and method for detecting a fluid leaked from a target site of a subject are provided. The sensor patch (100) includes a first detecting unit (127), a second detecting unit (128), and a patch body (110). The first detecting unit (127) includes a first pair of sensors (120A) respectively having a first end (121A) configured to be placed approximating the target site, while the second detecting unit (128) includes a second pair of sensors (120B) respectively having a first end (121B) configured to be placed away from the target site. Each sensor includes a conductive wire (125) and an insulating sheath (126) encapsulating the conductive wire (125) in a manner that a portion of the first end (121A, 121B) of the conductive wire (125) is exposed yet without directly contacting the subject's skin. The patch body (110) has an adhesive surface (104) for securing the first and second detecting units (127, 128) to the subject. The sensor patch enhances the detection specificity.