A differential voltage measuring system includes two electrodes that are connected to a patient at an input and make available a respective measurement contact at an output. A shunt resistor is connected in series with the second electrode. A first amplifier circuit has a first input for a first signal from the first electrode, a second input for a second signal from the second electrode, and an output. A second amplifier circuit has a first input that is connected in series with the shunt resistor, a second input that is connected in parallel with the shunt resistor, and an output. A first signal detection unit is provided at the output of the first amplifier circuit, and a second signal detection unit is provided at the output of the second amplifier circuit. The second signal detection unit detects the signal from the second amplifier circuit as a measurement variable.