Thermometer basics: Taking your child's temperature

Thermometer choices got you baffled? Understand the different thermometer options — and when to seek medical help for a fever.

By Mayo Clinic Staff

If your child feels warm or seems under the weather, it's probably time to take his or her temperature. Sounds simple enough — but if you're new to it, you might have questions. Which type of thermometer is best? Are thermometer guidelines different for babies and older children? Here's what you need to know to take your child's temperature.

Thermometer options

A glass mercury thermometer was once a staple in most medicine cabinets. Today, mercury thermometers are no longer recommended because they can break and allow mercury to vaporize and be inhaled. When choosing a thermometer, consider these options:

  • Digital thermometers. These thermometers use electronic heat sensors to record body temperature. They can be used in the rectum (rectal), mouth (oral) or armpit (axillary). Armpit temperatures are typically the least accurate of the three.
  • Digital ear thermometers (tympanic membrane). These thermometers use an infrared ray to measure the temperature inside the ear canal. Keep in mind that earwax or a small, curved ear canal can interfere with the accuracy of an ear thermometer temperature.
  • Temporal artery thermometers. These thermometers use an infrared scanner to measure the temperature of the temporal artery in the forehead. This type of thermometer can be used even while a child is asleep.

Digital pacifier thermometers and fever strips are not recommended.

Safety tips

Carefully read the instructions that come with the thermometer. Before and after each use, clean the tip of the thermometer with rubbing alcohol or soap and lukewarm water and then rinse with cool water. If you plan to use a digital thermometer to take a rectal temperature, get another digital thermometer for oral use. Label each thermometer, and don't use the same thermometer in both places.

For safety — and to make sure the thermometer stays in place — never leave your child unattended while you're taking his or her temperature.

Nov. 06, 2015 See more In-depth