Abstract: The invention is directed toward a magnetic valve reader used as an indicator tool. The magnetic valve reader determines a location and an orientation for a magnetic indicator device to indicate a device setting of an implantable medical device. The implantable medical device includes the magnetic indicator device coupled to a valve on the implantable medical device. External magnetic fields, specifically the Earth's magnetic field, may interfere with the compass and create an incorrect device setting indication. The electronic reader estimates the external magnetic fields to subtract the estimate from received data to minimize any influence that external magnetic field has on the accuracy of the device setting measurement.