Fluid containers having a volume marking(s) and conductive element(s) disposed at the volume marking(s) and a common conductive element are provided. For example, the fluid container has a wall forming the volume. The conductive element(s) and the common conductive element have a portion disposed within the volume and a portion external to the volume. The container further has a RFID tag, where the conductive element(s) and the common conductive element are connected thereto via respective conductive wires. A fluid detection system having the fluid containers is also provided. The system comprises one or more containers and a patient site monitor having a RF reader that interrogates the RFID tag at a preset interval. Responsive to the signal, the tag supplies a predetermined current to the conductive element and the common conductive element and detects a voltage and generates an alert based on the same.
