Are you measuring your child’s temperature correctly?

Millions of pediatricians and emergency rooms are visited every year by parents with their child because of fever.  Fever is one of the most concerning symptoms to parents because of its association with illness as well as overall poor feeling by the child.

First, it is important to review that the standard accepted definition of fever is a temperature of 100.4 degrees Fahrenheit (38 degrees Celsius).  Fever can be one of many symptoms of having an illness and actually is a good sign!  Fever means that your child’s body has recognized that there is a foreign process occurring in their body (like an infection) and has started fighting the infection.

Is 98.6 the normal temperature?

In a word, yes.  98.6 degrees Fahrenheit is a normal temperature.  However, did you know that temperatures normally vary throughout the day?  Normal body temperature can vary as much as 1.5 degrees Fahrenheit (high or low).  Additionally, body temperatures are usually highest in the late afternoon and lowest after midnight.

What is the best way to take a temperature?

For measuring temperature, the rectal temperature is the “gold standard.”  This is especially important in newborns less than 3 months old as they are more susceptible to severe infections.  Digital thermometers are generally used most often because they are easy to read and do not contain the toxic chemical, mercury.  The American Academy of Pediatrics advises parents not to use mercury-containing glass thermometers because of the possibility of toxic exposure.  Additionally, all thermometers should be rinsed and cleaned prior to use and washed thoroughly before being put away.

Rectal temperature

This is the preferred method to obtain a true temperature in determining whether or not a child has a fever.  Place a small amount of water-soluble lubricant on the tip of the thermometer and put it between your fingers so that only 2-3cm of the thermometer will be placed in the rectum.  Use the pads of your fingers against your child’s bottom as a brace so that you do not insert the thermometer too far.

Tip: Ask the nurse or pediatrician to show you how to correctly take a rectal temperature prior to discharge from the hospital, or at your first newborn visit!

  • Rinse the thermometer with cool water before using (Hot water rinses before use can cause the reading to be falsely elevated)
  • This can be done with the child lying their back with their feet held in the air as if your were cleaning them after a diaper change or while they are on their stomach.
  • Hold the thermometer in place until your hear the “beep.”  Remove and wash the thermometer with soap and water before putting it away.
  • Have one thermometer labeled for rectal use only!  Do not use the same thermometer for measurements in other areas of the body, regardless of how well your wash it.

Oral (mouth) temperature

This method requires that a child be able to hold the thermometer under their tongue for several minutes.  This can usually be done around age 5, but as many of you know, asking a 5 year old who does not feel well to do anything for several minutes can be quite a challenge.

  • Using a clean thermometer, place the bulb (metal tip) under the tongue and hold the thermometer in place until it beeps.
  • Their mouth must also be closed tightly around the thermometer without biting on it to avoid false readings
  • Wait several minutes to take an oral temperature if the child recently had any hot or cold liquids to avoid false readings

Studies comparing oral to rectal temperatures have shown them to be close in measurement when taken correctly, making this an acceptable way to measure temperature. However, the oral temperature can vary up to 1.5 degrees Fahrenheit from the rectal temperature if it is not measured correctly.

Axillary (armpit) temperature

This method is one of the less invasive techniques to measure temperature.  A clean thermometer should be placed in the center of their armpit for measurement, with the arm then placed at the side. This method is one of the least reliable as measurements can be off by as much as 4 degrees Fahrenheit!

  • The thermometer must be held under the armpit for a longer period of time to get a stable reading
  • The armpit must be dry – Sweat can cause false readings and excessive drying of the area can cause excessively high temperatures because of heat created by friction

Aural (ear) temperature

This method is more frequently used by parents with older infants and young children because of ease of operation and speed of measurement.  Many of these thermometers can measure temperature after just a few seconds of placement.

The thermometer must be placed correctly in the ear canal in order to receive an accurate reading.  When done correctly, this method reflects an accurate measurement of temperature.

False readings are common. In a study looking at parents vs. nurses – parents failed to detect fever 25% of the time using an ear thermometer

Readings can also be affected if there is too much wax in the ear. Cotton tipped swabs should never be used to clean out your child’s ears due to of risk of puncturing the eardrum. There are safer methods to remove ear wax at home, such as ear drops.  Or this can be done by a physician using an ear curette.

Readings are affected by ambient temperature, especially if coming in from cold weather and not allowing the ears to warm prior to taking a measurement

Temporal (forehead) temperature

This thermometer uses an infrared beam which measures the temperature when pointed at the child’s forehead. These have been shown to be widely inaccurate and are affected by ambient temperature and skin temperature which does not accurately reflect the true core body temperature. Forehead temperatures measured with tape-like strips are also widely inaccurate and affected by ambient temperature.

These are not recommended for obtaining an accurate temperature

Discuss with your pediatrician what the best way is to measure your child’s temperature.  For more questions on fever and measuring temperature, please consult with your child’s physician.

The amount of medication needed to reduce fever is based on your child’s weight.  Ask your pediatrician what your child’s new dose amount is at each visit.