Besides following the instructions on your thermometer, here is advice from doctors on getting accurate readings:
Use a digital thermometer. Medical associations no longer recommend glass thermometers filled with mercury, an environmental toxin.
Time it right. Eating something hot or cold, hot baths, layers of warm clothing and vigorous exercise can throw off readings.
For oral readings: Keep the thermometer under your tongue, toward the back of your mouth. Use your lips to close your mouth around it -- don't bite down on it. Breathe through your nose, and don't open your mouth to talk.
For rectal readings: Place the child on the stomach on your lap or a flat surface. Rub a little petroleum jelly on the tip of a rectal thermometer and insert it 1/2 to 1 inch inside the rectum. (Never push if you meet resistance.)
For ear readings: If a thermometer comes with plastic covers, dispose of them after a single use. Gently place the thermometer into the entrance of the ear canal; again, don't push.
For underarm readings: Make sure the child's armpit is dry, and take off the child's shirt so only skin will touch the thermometer.
DAILY PRESS (NEWPORT NEWS, VA.)