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Best Ways to Take a Temperature

There are several ways to take your child’s temperature. What type of thermometer should you select? The American Academy of Pediatrics no longer recommends mercury thermometers because these glass thermometers may break and, as their mercury vaporizes, it can be inhaled, resulting in toxic levels. Digital electronic thermometers are better choices. 

  • Digital devices can measure temperatures in your child’s mouth or rectum. As with any device, some digital thermometers are more accurate than others. Follow the manufacturer’s instructions carefully, and be sure the thermometer is calibrated.
  • Ear thermometers are another acceptable choice. Their accuracy depends on the ability of the beam emitted by the device to reach the eardrum. Thus, some of these devices may not be as reliable because of earwax or a small curved ear canal. For that reason, most pediatricians prefer that parents use digital electronic thermometers.

Use a digital thermometer (which shows the temperature in numbers in a small window), and avoid mercury thermometers. Whatever approach you use, clean the thermometer with lukewarm soapy water or rubbing alcohol before each use, and then rinse with cool water.

  • To take the temperature in your child’s bottom (rectally), turn on the digital thermometer and then put a small amount of lubricant, such as petroleum jelly, on the small end of it. Place your child across your lap or on something firm, either faceup or facedown (if he’s facedown, put one hand on his back; if he’s faceup, bend your child’s leg to his chest, resting your free hand on the back of his thighs). Then gently insert the small end of the thermometer in your child’s bottom (or rectum), putting it in about 1⁄2 inch to 1 inch. Hold the thermometer in place for about one minute, or until the device signals that it’s done (by beeping or lighting up). Remove it and read the number. Taking a rectal or oral temperature is more accurate than taking it under your child’s arm. Also, use one digital thermometer labeled “oral,” and another one labeled “rectal.” Don’t use the same thermometer in both places.
  • At ages four or five years old, you also can take your child’s temperature by placing the thermometer in his mouth (orally). After turning on the thermometer, place the small end under your child’s tongue, toward the back of his mouth. Ask him to close his mouth around the thermometer, and hold it in place. Remove it after about a minute, or until you hear the thermometer “beep” or see it light up. Then read the number.
  • Temporal artery thermometers are also available. While these are simple to use even while your child is asleep, they are relatively new so their reliability has not yet been verified.
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Caring for Your Baby and Young Child: Birth to Age 5 (Copyright © 2009 American Academy of Pediatrics)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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