April 10, 2016
1481
Q: What is the best way to take a body temperature to detect a fever?
A: Many of us grew up with a mercury thermometer in our medicine cabinet. Since mercury is toxic, these thermometers are no longer recommended for use. If you still happen to own a mercury thermometer, you should find a local hazardous waste collection site and dispose of it properly.
Nowadays, there are several options available to read body temperature and, depending on the age of the person, some are more suitable than others. The most common and least expensive, is the digital thermometer (records temperature in one minute or less using electronic heat sensors) which can be used in the rectum, mouth (oral) or the armpit.
If you wish to use both the rectal and the oral method, it is important that you do not use the same thermometer for both places. Even if you clean the rectal thermometer, it is strongly advised to have two digital thermometers and clearly mark one for rectal and the other for oral or mouth use.
Rectal temperature provides the most accurate method, especially for young children and infants (digital thermometers can be used rectally in infants), yet least-favoured by the parents. To use rectally, lubricate the tip of the thermometer with petroleum jelly and then insert it one-half to one inch (1.3 to 2.5 centimetres) and wait until the thermometer signals to you that it has recorded the temperature.
The armpit method is considered the least accurate reading of the three. If using this method, ensure that the thermometer touches skin and not clothing and also that it is held in place until it signals that it is done.
The oral method is suitable for adults and older children. Since it relies on the person being able to keep the thermometer in his/her closed mouth long enough to get an accurate reading, it is not a good choice for younger children or people who are mouth breathers. Keep in mind that food and beverages may affect oral temperature readings so be sure to wait 15 minutes after eating or drinking to take an oral temperature.
Digital ear thermometers (tympanic thermometers) have been on the market for some time now. They use an infrared ray to measure the temperature in the ear canal. The accuracy is dependent on having the correct positioning in the ear and can be affected by difficult (or even impossible) to control factors such as earwax or having a small, curved ear canal. They are more expensive than the regular digital thermometer but many people like the quick response time and ease of use. They are recommended only for people who are older than six months of age.
Temporal artery thermometers (forehead thermometers) are a more recent method of measuring body temperature. They use an infrared scanner to read the temperature of the temporal artery in the forehead while gently moving the thermometer across the forehead without touching the skin. Like the ear thermometers, they are quick but also expensive. They can be used in people three months of age and older; however, more recent studies are reporting that they can be used in infants and can provide an accurate alternative to the rectal method (which may put some parents mind at ease).
There are also digital pacifier thermometers that are available but not highly recommended as they need to remain in the mouth for three to five minutes to obtain an accurate reading. This is difficult for any child and likely even more troublesome if they are sick.
In summary, while the rectal thermometer is the most accurate in the very young (which is the age group we are most concerned with when it comes to fever due to the higher risk of complications such as seizures or brain damage), it is not a great deal of fun for either parent nor child. We would suggest a temporal thermometer (which is more accurate than an ear or mouth thermometer) for ease of use, accuracy and the ability to take your child’s temperature without waking him/her (a massive, massive advantage!).
You could make an argument to keep a digital thermometer around in case the temperature is higher than you are comfortable with in order to use it rectally to get the most accurate reading but we would suggest if you are getting up to those sorts of temperatures, you should already be bundling up your child for a visit to the hospital emergency room.
A child less than three months of age should be taken to hospital with any fever at all. From three to six months of age, a temperature equal to or above 38.3 degrees Celsius; and at six months or older, at 39.4 degrees Celsius, or if they have at least two accompanying symptoms such as a cough, sore throat, runny/stuffy nose, headache, chills, fatigue or diarrhea with a fever of 38.9 degrees Celsius.
Now that we discussed the various types of thermometers, it is important to know that normal body temperatures vary depending on the person and also on the method used. Generally, the following temperatures would indicate a fever:
A rectal, ear or forehead reading of 38°C (100.4°F) or higher
An oral reading of 37.8°C (100°F) or higher
An armpit reading of 37.2°C (99°F) or higher
For more information on this or any other topic, contact the pharmacists at Gordon Pharmasave, Your Health and Wellness Destination.
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