If for any reason the Sensor does not work, an error message will appear on the reader prompting users to replace the Sensor.  Users should not ignore symptoms that may be due to low or high blood glucose. If users have symptoms that do not match the FreeStyle Libre system reading or if users suspect that their reading may be inaccurate, check the reading by conducting a fingerprick test using a blood glucose meter. If users are experiencing symptoms that are not consistent with glucose readings, users should consult their healthcare professional.