A medical device system comprises a reservoir configured to store a therapeutic fluid and a medical pump configured to deliver the therapeutic fluid from the reservoir to a patient. The system also comprises a sensor that can detect a characteristic associated with the pump and a processor to determine if the characteristic detected indicates the reservoir is empty or near empty. The characteristic may comprise a property associated with the energization of an actuation mechanism configured to be energized to provide a pump stroke. The characteristic may also comprise a characteristic of a noise made by an actuator within the pump at the end of a pump stroke.
