Thermometers aren’t exactly a newfangled concept when it comes to the medical industry. However, the range of different models available certainly is.
From a remote forehead or ear thermometer to a contact device used on the mouth, armpit or rectum, this list explains the pros, cons and accuracy of the different types of thermometers.
Gone are the days of glass mercury thermometers
What was once considered a staple in the medicine cabinet is now becoming defunct as safer digital devices saturate the market. However, it pays to consider how glass thermometers work, and just why they are no longer recommended.
In essence, these thermometers rely on mercury encased in glass to measure body temperature via the rectum or mouth. Mercury, which remains a liquid in all temperatures, is used because it expands with heat, hence slowly rising up the glass temperature gauge to provide a manual reading.
- Pros: Inexpensive and does not rely on batteries.
- Cons: Slow to administer and can cause injury or exposure to toxic chemicals if the glass breaks and mercury leaks.
- Accuracy: Requires calibration with each use, making it less accurate than digital thermometers.
It should be noted that if you still have a mercury thermometer at home, it is important to seek out a hazardous waste collection site rather than simply throwing the device in the rubbish bin.
Electronic contact thermometers for the forehead, armpit, mouth or rectum
These nifty gadgets rely on electronic heat sensors to record the body’s temperature. Once taken, a simple digital display will provide the temperature reading. Contact thermometers must make contact with the body to gauge a reading – they can be used against the forehead, placed under the armpit, popped in the mouth or inserted into the rectum.
- Pros: Fast to administer (usually under a minute) and appropriate for all ages.
- Cons: Can cause discomfort and cannot be used within 15 minutes after eating or drinking.
- Accuracy: Rectal readings are most accurate for newborns and children up to the age of three, while oral readings are most accurate for older children and adults. Armpit readings are usually regarded as the least accurate.
Remote temporal artery thermometers (also known as forehead thermometers)
This type of device relies on infrared scanning to measure the temperature of the forehead’s main artery. That means no contact with the skin is necessary: the thermometer is simply directed towards the forehead for a few seconds in order to generate a temperature reading.
- Pros: Fast to administer, easily tolerated and appropriate for all ages.
- Cons: Costlier option than other thermometers.
- Accuracy: External conditions (such as cold temperatures and sweaty foreheads) as well as user technique (for instance, holding the thermometer too far back) can affect the accuracy.
Remote tympanic thermometers (also known as ear thermometers)
The tympanic membrane is the medical term for the ‘eardrum’, hence these thermometers measure the temperature inside the ear canal. The device sits just outside the ear, using infrared rays to take a reading.
- Pros: Fast to administer and easily tolerated (if positioned properly).
- Cons: Not recommended for infants younger than six months of age.
- Accuracy: The shape of the ear or the presence of earwax can interfere with the accuracy.