Digital "Pen" Style Thermometer and Proper Techniques

Taking a Proper Temperature Using a Digital “Pen” Style Thermometer

  • If you’re taking a child’s (ages 2+) temperature orally, place the tip of the thermometer under the tongue, towards the back of the mouth, and leave it there as directed by the instructions. The child needs to breathe through their nose. Do not let your child bite on the thermometer or talk. The child must be old enough to cooperate and often this method is used in children over 4 or 5 years of age. Digital thermometers may beep when they are ready to be read. Wait 30 minutes before taking the temperature if a child has consumed hot or cold food or drinks.
  • When taking a child’s temperature rectally, place him or her belly-down across your lap. Coat the tip of the thermometer with petroleum jelly and insert it half an inch into the rectum. Stop if you feel any resistance. Never let go of the thermometer. This method often works best with infants.
  • An underarm (axillary) temperature is a safe way to take the temperature of toddlers and children under 4 years of age. Place the thermometer in the child’s underarm and hold the arm against the child’s body so that the tip of the thermometer is covered. However, underarm (axillary) measurements are not as accurate as rectal measurements and should not be used for tracking a fever.


Predictive Technology
“Pen” style fever thermometers that measure in less than 10 seconds use “predictive” technology. In effect, these thermometers use an algorithm based on how quickly the temperature rises to “predict” the ultimate temperature faster.

In most cases the prediction will be exactly or very close to the actual temperature, but as the devices get faster, the potential for error grows. If users are in doubt, they should confirm with another device.