Normal body temperature is often defined as 98.6 degrees Fahrenheit (F) or 37 degrees Celsius (C). Whenever a person is ill or feels hot or cold to the touch, it is important to take the temperature. If a healthcare professional is called during an illness, he or she will often ask for the temperature of the ill person.
Who is a candidate for the procedure?
A person's temperature may be checked when fever, or higher-than-normal body temperature, is suspected. Examples of conditions that might cause fever include:
- infections such as group A streptococcal infections, pneumonia, urinary tract infection, or meningitis
- inflammatory conditions, such as arthritis
- tissue injuries
- being in a hot environment too long, causing a heat emergency
- drug interactions
- aspirin toxicity
A person who might have hypothermia, or an abnormally low body temperature, can also have their temperature measured. Hypothermia is usually caused by being in the cold for too long.
How is the procedure performed?
There are 4 common methods for taking a temperature:
- in the mouth, which is known as an oral temperature
- in the anus, which is called a rectal temperature
- in the armpit, which is known as an axillary temperature
- in the ear, which is called a tympanic temperature
Temperature strips, which are liquid crystal strips applied to the forehead, and temperature-sensitive pacifiers may not be as accurate as a regular thermometer. If these are used, a child may have a fever despite a "normal" reading.
A baby's temperature can be taken either in the anus or in the armpit. It would be dangerous to take an oral temperature on a baby, who might bite the thermometer. Taking a baby's temperature in the ear may be difficult. Parents should check with the baby's healthcare professional for the best method and what temperatures should be reported.
Temperature can be taken in the mouth in children over the age of 4 years as long as they follow instructions.
How to Take an Oral Temperature:
1. For accuracy, wait at least 10 minutes after hot or cold fluids have been taken, or cigarettes have been smoked.
2. Select a glass thermometer that has a "bulb" or silver end that is long and thin. If using a digital thermometer, make sure it is in the correct "on" mode.
3. Gently shake until the colored line on the glass thermometer is below 95 degrees F.
4. Place the thermometer in the person's mouth under the tongue on one side, and slide well back into the mouth. Have person close the lips, and to avoid biting the thermometer.
5. Hold thermometer in place for 3 to 4 minutes.
6. Remove the thermometer from the mouth and read it. On a digital thermometer, simply read the numbers. On a glass thermometer, hold it horizontally and turn it slowly until the temperature at the highest position of the colored column can be read. Usually the space between the larger marks is one degree; the space between the short marks is 0.2 degrees (or two tenths of a degree).
How to Take a Rectal Temperature:
1. Select a rectal glass thermometer, which has a rounder bulb at the end, or use a digital thermometer.
2. Shake the glass thermometer until the colored line is below 95 degrees F.
3. Moisten the lower portion of the thermometer with Vaseline or other lubricant.
4. Place the infant on his/her stomach, on a firm surface, or across your lap.
5. Spread the buttocks to expose the anal opening. Hold the thermometer one inch from the bulb, and gently insert it into the rectum. Insert the thermometer just far enough that the bulb, or silver tip, is completely covered. Do not insert thermometer more than one inch.
6. Do not let go of the thermometer. Carefully hold it in place for 3 to 4 minutes.
7. Remove the thermometer gently and read it. Rectal temperatures are generally 0.5 to 1 degree F higher than oral temperatures.
How to Take an Axillary Temperature:
1. Use a glass or digital thermometer. Make sure the colored line on the glass thermometer is under 95 degrees F. before taking the temperature.
2. Hold the thermometer in the clean, dry armpit, making sure that the bulb is completely covered between the person's arm and side. Hold the arm down.
3. Hold the thermometer in position for 3 to 4 minutes.
4. Remove the thermometer and read the temperature. Normal axillary temperatures are 1 degree F lower than oral temperatures.
How to Take a Tympanic Temperature:
1. Use a thermometer especially designed for ear temperatures.
2. Hold the thermometer firmly at the opening to the child's ear, and press the button.
3. Remove the thermometer and read the temperature.
Current Pediatric Diagnosis and Treatment, Twelth Edition, 1998, Hay et al.