If the thermometer is handled at length or if there is a significant temperature difference with respect to the room temperature, a countdown will appear on the display indicating that you should wait until automatic temperature calibration has been completed. Without touching the thermometer, wait until the countdown has run its course and automatic quick calibration is completed. The countdown will continue updating as long as differences in temperature are detected (for example, because the thermometer has been handled).. You can take a reading before the countdown has run its course, although, in this case, accuracy cannot be guaranteed, particularly if the temperature is rising. At the end of the countdown, the thermometer can take sufficiently accurate readings. When the thermometer is in stand-by mode, “RE” appears on the display indicating that automatic quick calibration has been performed.