PARENT CARE: FEVER, HOW TO TAKE
Definition of Fever
temperature above 100.4°F (38.0°C).
Oral temperature above 99.5°F (37.5°C).
Axillary (armpit) temperature above 99.0°F (37.2°C).
Pacifier temperature above 100°F (37.8°C). New
digital electronic ones are accurate.
Ear (tympanic) temperature above 100.4°F (if in rectal mode)
or above 99.5°F (if in oral mode). (Note: Not reliable for less than
6 months old.)
Temporal artery (TA) temperature above 100.4 F (38.0 C) (Note:
more reliable than tympanic thermometers, but not to be used for children under
6 months old)
Where to Take the Temperature
Temperatures measured rectally are the most accurate.
Temperatures measured orally, by electronic pacifier, or by ear canal are
also accurate if done properly. Temperatures measured in the armpit are the
least accurate, but they are better than no measurement.
Age less than 3 months old (90 days old):
An armpit temperature is preferred for reasons of safety and is adequate for
screening. If the armpit temperature is above 99°F (37.2°C), check
it with a rectal temperature. The reason you need to take a rectal temperature
for young infants is that if they have a true fever, they need to be evaluated
Age less than 4 or 5 years old:
A rectal or electronic pacifier temperature is preferred. An axillary
(armpit) temperature is adequate for screening if it is taken correctly. An
ear thermometer can be used after 6 months old.
Age older than 4 or 5 years old:
Take the temperature orally (by mouth) or by ear thermometer.
How to Take Rectal Temperatures
child lie stomach down on your lap.
Put some petroleum jelly on the end of the thermometer and on
the opening of the anus.
Slide the thermometer gently into the opening of the anus for
about 1-inch. If your child is less than 6 months old, put it in only
about ¼ to ½ inch (inserting until the silver tip disappears is
about ½ inch).
Hold your child still and leave the thermometer in 2 minutes
with a glass thermometer (about 20 seconds with a digital electronic thermometer).
Your child has a fever if the rectal temperature is
above 100.4°F (38°C).
How to Take Armpit Temperatures
tip of the thermometer in an armpit. Make sure the armpit is dry.
Close the armpit by holding the elbow against the chest for
4 or 5 minutes.
Your child has a fever if the armpit temperature is above 99.0°F
(37.2°C). If you have any doubt, take your child's temperature by
How to Take Oral Temperatures
your child has not had a cold or hot drink in the last 30 minutes.
Put the tip of the thermometer under one side of the tongue
and toward the back. It's important to put it in the right place.
Have your child hold the thermometer in place with his lips
and fingers (not teeth) for 3 minutes with a glass thermometer (about 30 seconds
with a digital electronic thermometer). Keep the lips sealed.
Your child has a fever if the temperature is above 99.5°F
How to Take a Digital Electronic Pacifier
child suck on the pacifier until it reaches a steady state, and you hear a beep.
This usually takes 3 to 4 minutes.
Your child has a fever if the pacifier temperature is above
How to Take an Ear Temperature
thermometer reads the infrared heat waves released by the eardrum.
An accurate temperature depends on pulling the ear backward
to straighten the ear canal (back and up if over 1 year old).
Then aim the tip of the ear probe midway between the opposite
eye and earlobe.
The biggest advantage of this thermometer is that it measures
temperatures in less than 2 seconds. It also does not require cooperation
by the child and does not cause any discomfort.
Limitation: if your child has been outdoors on a cold day, he
needs to be inside for 15 minutes before taking the temperature. Earwax,
ear infections and ear tubes, however, do not interfere with accurate readings.
This information is not intended be a substitute for professional medical
advice. It is provided for educational purposes only. You assume full
responsibility for how you choose to use this information.
Pediatric HouseCalls Online. Copyright © 2000-2004
Barton Schmitt, M.D. FAAP
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