Learning About Taking Your Child's Temperature

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Electronic and ear thermometers

What is body temperature?

Body temperature is a measure of how well your child's body can make and get rid of heat. You can find out what your child's temperature is by using a thermometer. There are specific types of thermometers to use in different parts of the body.

A rectal or ear temperature reading is about 0.5°F (0.3 C) to 1°F (0.6°C) higher than an oral reading. A temperature taken in the armpit is about 0.5°F (0.3 C) to 1°F (0.6°C) lower than an oral reading. Rectal thermometers are thought to be the most accurate way to check a child's temperature.

Experts say that a rectal temperature in a child over 100.4°F (38°C) is a fever.

The method you use to take a child's temperature depends on the child's age:

  • For a child age 0 to 3 months, it's best to use a rectal thermometer only.
  • For a child age 3 months to 3 years, you can use a rectal, armpit, or ear thermometer. But rectal is best.
  • For a child age 4 to 5 years or older, use a rectal, oral, armpit, or ear thermometer.

How do you take your child's temperature by mouth?

Before you take a temperature, read the instructions for how to use your type of thermometer.

Oral (by mouth) is the most common method of taking a temperature. To get an accurate reading, your child must be able to breathe through the nose. If your child can't, then use the rectum, ear, or armpit to take the temperature.

  1. Place the thermometer under your child's tongue, just to one side of the center.

    Your child's lips should be closed tightly around it.

  2. Leave the thermometer in place for the required amount of time.
  3. Remove the thermometer and read it.
  4. Clean the thermometer with cool, soapy water, and rinse it off before you put it away.

How do you take your child's rectal temperature?

A rectal thermometer is the most accurate way to take a temperature. It is recommended for children younger than age 6.

  1. Put a lubricant jelly or petroleum jelly, such as Vaseline, on the tip of the thermometer.

    This will help you insert it easily.

  2. Turn your child facedown on your lap or on a flat covered or padded surface, such as a bed.

    Choose a quiet place so that the child won't be distracted or move around too much.

  3. Insert the thermometer.
    1. Spread your child's buttocks apart with one hand.
    2. Gently insert the bulb end of the rectal thermometer about ½ to 1 inch into the rectum with your other hand. Don't force it into the rectum.
    3. Hold the thermometer in place with two fingers close to the rectum (not near the end of the thermometer). Pressing your child's buttocks together will help keep the thermometer in place.
  4. Leave the thermometer in place for the required amount of time.
  5. Remove the thermometer and read it.
  6. Clean the thermometer with cool, soapy water, and rinse it off before putting it away.

After a thermometer has been used to take a rectal temperature, do not use it to take an oral temperature.

How do you take your child's armpit temperature?

  1. Place the thermometer under your child's arm with the tip in the center of the armpit.
  2. Press your child's arm against the body, and leave the thermometer in place for the required amount of time.
  3. Remove the thermometer and read it.

    An armpit temperature reading may be as much as 1°F (0.6°C) lower than an oral temperature reading.

  4. Clean the thermometer with cool, soapy water, and rinse it off before putting it away.

How do you take your child's ear temperature?

  1. Check that the ear probe is clean.

    If it's dirty, wipe it gently with a clean cloth. Do not put the thermometer in water.

  2. To keep the probe clean, use a disposable probe cover.

    Attach the disposable cover to the probe.

  3. Turn the thermometer on.
  4. Pull your child's earlobe up and back.
  5. Center the probe tip in your child's ear, and push gently inward toward the eardrum.
  6. Press the "on" button to display the temperature reading.
  7. Remove the thermometer, and throw away the used probe cover.
  8. Use a new probe cover each time you take an ear temperature.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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