Step 1. Do not drink or eat 15 minutes prior to taking a temperature reading.
Step 2. Do not breathe heavily through the mouth prior to taking temperature.
Step 3. Position the thermometer in the correct area, as close to the center as possible, under the tongue.
Step 4. Ensure there is no air left in the mouth while keeping the thermometer in place.
Step 5. Wait at least 20 seconds even if the thermometer indicates it is already ready.
Step 6. Add several tenths of degrees to the temperature. When on a threshold of a fever, it is better to confirm the temperature by doing a rectal measurement just to be sure.