Getting an accurate measurement of your
child's temperature takes practice. If you have questions
about these instructions, ask your health care provider to
show you how it's done. Then ask your provider to watch you
do it.
Where is the
best place to put the thermometer?
A rectal (in the bottom) temperature is the
most accurate. Temperatures measured by mouth, by electronic
pacifier, or by ear are also accurate if done properly.
Temperatures measured in the armpit are the least accurate,
but they are better than no measurement. The best place to
use the thermometer depends on the age of your child.
- For a baby less than 3 months old (90
days old):
An armpit temperature is best because it
is safest and works fine for a quick check. If the
armpit temperature is over 99°F (or 37.2°C), double
check it with a rectal temperature. It is good to double
check with a rectal temperature because if your baby has
a true fever, you should see a health care provider
immediately.
- For a child between 3 months and 4 or
5 years old:
A rectal temperature or electronic
pacifier thermometer are best. Using an ear thermometer
is fine after 6 months old. An armpit temperature is
fine for a quick check if done correctly.
- For a child older than 4 or 5 years
old:
Take the temperature by mouth (orally).
How to Take a Rectal Temperature
- If you are using a glass thermometer,
shake until the mercury line is below 99°F (37.2°C). If
you are using a digital thermometer, turn it on.
- Have your child lie stomach down on
your lap.
- Before you insert the thermometer, put
some petroleum jelly on the end of the thermometer and
on the opening of the bottom (anus).
- Insert the thermometer gently into the
bottom about 1 inch. If your child is younger than 6
months old, gently insert the thermometer only 1/4 to
1/2 inch. If you put the thermometer in just until the
silver tip disappears, that is about 1/2 inch. Never try
to force it past any resistance. Forcing could damage
the bowel.
- Hold your child still while the
thermometer is in.
- If you are using a glass thermometer,
leave it in your child's bottom for 2 minutes before you
take it out. If you are using a digital thermometer,
take it out when you hear the correct signal (usually a
series of beeps).
- Read the temperature on the
thermometer. If you are using a glass thermometer, you
may have to rotate the thermometer until you can see the
end of the mercury line.
- If the rectal temperature is over
100.4°F (38°C), your child has a fever.
How to Take Armpit (Axillary) Temperatures
- If you are using a glass thermometer,
shake it until the mercury line is below 98.6°F (37°C).
- Place the tip of the thermometer in a
dry armpit.
- Close the armpit by holding the elbow
against the chest for 4 or 5 minutes. Do not remove it
before 4 minutes have passed.
- After 4 or 5 minutes take the glass
thermometer out and read the temperature by finding
where the mercury line ends. You may need to rotate the
thermometer until you can see the mercury. If you are
using a digital thermometer, remove it after you hear
the signal (usually a series of beeps) and read the
temperature on the screen.
- Your child has a fever if the armpit
temperature is over 99°F (37.2°C). If you're not sure if
it is correct, check it by taking a rectal temperature.
How to Take Oral (Mouth) Temperatures
- Be sure your child has not had a cold
or hot drink in the last 30 minutes.
- If you are using a glass thermometer,
shake the thermometer until the mercury line is below
98.6°F (37°C). If you are using a digital thermometer,
turn it on.
- Place the tip of the thermometer under
one side of the tongue and toward the back. An accurate
temperature depends on putting it in the right place.
Ask your health care provider to show you where it
should go.
- Have your child hold the thermometer
in place with his lips and fingers (not his teeth). He
should breathe through his nose, keeping his mouth
closed. If your child can't keep his mouth closed
because his nose is blocked, suction out the nose.
- Leave the glass thermometer in the
mouth for 3 minutes. Leave a digital thermometer in the
mouth until you hear the correct signal (usually a
series of beeps).
- Read the temperature. If you are using
a glass thermometer, you may need to turn the
thermometer until you can see where the mercury line
ends.
- Fever is an oral temperature over
99.5°F (37.5°C).
How to Take a Electronic Pacifier Temperature
- Have your child suck on the pacifier
until the temperature stops changing and you hear a
beep. This usually takes 3 to 4 minutes.
- Read the temperature. Your child has a
fever if the pacifier temperature is over 100°F
(37.8°C).
How to Take an Ear Temperature
- 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.)
- Pull the ear backward to straighten
the ear canal.
- Place the end of the thermometer into
your child's ear canal and aim the probe toward the eye
on the opposite side of the head. Then press the button.
- In about 2 seconds you can read the
temperature.
- Your child has a fever if the ear
temperature is over 100.4°F (38°C).
Types of Thermometers
- Glass (with
mercury) thermometers
This type of thermometer has been around
since 1870. These are the least expensive thermometers.
They have some disadvantages. They measure temperatures
slowly and are often hard to read. If broken, they cause
a mercury spill which can be harmful and difficult to
clean up. The American Academy of Pediatrics urges
parents not to use mercury thermometers.
Glass thermometers come in two forms,
oral with a thin tip and rectal with a rounder tip. This
difference is not too important. If necessary, a rectal
thermometer can be used in the mouth as long as the
thermometer is cleaned with rubbing alcohol. An oral
thermometer can be used in the rectum if you are extra
careful when you put it in.
- Digital
electronic thermometers
Digital electronic thermometers measure
temperatures with a heat sensor and require a button
battery. They measure temperatures quickly, usually in
less than 30 seconds. The temperature is displayed in
numbers on a small screen. The same thermometer can be
used to take both rectal and oral temperatures.
A study in Consumer Reports magazine
found that digital thermometers were more accurate than
glass thermometers. Buy one for your family. They cost
about $10.00.
- Ear
thermometers
Many hospitals and medical offices now
take your child's temperature using an infrared
thermometer that reads the temperature of the eardrum.
In general, the eardrum temperature provides a
measurement that is as accurate as the rectal
temperature.
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. Ear
thermometers for use at home have been developed and
they cost $30 to $40.
- Digital
electronic pacifier thermometers
The new electronic pacifier thermometers
have a heat sensor and are powered by a button battery.
These pacifiers let you measure oral temperature in
younger children. They are quite accurate if 0.5°F is
added to the digital reading. It takes approximately 3
minutes to get a reading. They cost about $15.
- Temperature
strips
Liquid crystal strips put on the
forehead have been studied and have been found to be
inaccurate. They do not detect an elevated temperature
in most children with fever.
Touching the forehead is somewhat
reliable for detecting fevers over 102°F (38.9°C) but
tends to miss mild fevers.
Conversion of Degrees Fahrenheit (F) to Degrees Celsius (C)
Temperatures can be measured in degrees
Fahrenheit (F) or degrees Celsius (C). The table below shows
the temperatures in degrees Celsius that are equivalent to
temperatures measured in degrees Fahrenheit:
95 degrees F = 35 degrees C
96.8 degrees F = 36 degrees C
98.6 degrees F = 37 degrees C
99 degrees F = 37.2 degrees C
99.5 degrees F = 37.5 degrees C
99 degrees F = 37.2 degrees C
100 degrees F = 37.8 degrees C
100.4 degrees F = 38 degrees C
101 degrees F = 38.3 degrees C
102 degrees F = 38.9 degrees C
103 degrees F = 39.5 degrees C
104 degrees F = 40 degrees C
105 degrees F = 40.6 degrees C
106 degrees F = 41.1 degrees C
107 degrees F = 41.7 degrees C
108 degrees F = 42.2 degrees C
