Contact thermometers

The most common kind of contact thermometer uses electronic heat sensors to record body temperature. These thermometers can be used on the forehead, mouth, armpit or rectum. Most electronic thermometers have a digital display that shows you the temperature reading.

Rectal temperatures provide the most-accurate readings for infants, especially those 3 months or younger, as well as children up to age 3. Temperatures taken from the armpit are usually the least accurate. For older children and adults, oral readings are usually accurate — as long as the mouth is closed while the thermometer is in place.

The pros:

• Most electronic contact thermometers can record temperatures from the forehead, mouth, armpit or rectum — often in less than one minute.
• An electronic contact thermometer is appropriate for newborns, infants, children and adults.

The cons:

• Parents may worry about causing discomfort when taking a child's temperature rectally.
• You need to wait 15 minutes after eating or drinking to take an oral temperature. Otherwise, the temperature of your food or drink might affect the thermometer reading.
• It can be difficult for children — or anyone who breathes through the mouth — to keep their mouths closed long enough to get an accurate oral reading.

If you plan to use an electronic contact thermometer to take both oral and rectal temperatures, get two thermometers and label one for oral use and one for rectal use. Don't use the same thermometer in both places.