What are the types of medical thermometers?

medical thermometers

Medical thermometers were the inanimate protagonists of Thomas Mann’s The Magic Mountain, and today they are more prominent than ever, what with Ebola, SARS, and other viral and bacterial infections. At the same time, these devices are as helpful as they have always been in daily, minor medical conditions such as colds and the flu. Infrared models exist that do not touch the patient, but since the most common models are going to go in your mouth – or into that holiest of holies, the Temple of Sodom –, it goes without saying that you must choose wisely from the many current options.

Digital Thermometer

These have an electronic heat sensor on their tip that comes in contact with one of three body parts (mouth, rectum, or underarm) in order to provide the fastest, most accurate readings. Rectal measurements are the most precise for children aged 3 and younger; older children and adults can get off with oral readings. Rule of thumb: never go rectum-to-mouth.



·         Results are ready in a minute or less.

·         Appropriate for all ages.

·         Available in many shapes and sizes at different locations, such as grocery stores and pharmacies.

·         Rectal readings may be uncomfortable.

·         Must wait 30 minutes after eating or drinking to take oral temperature.

·         Nasal congestion may make it hard to keep mouth close long enough for an accurate reading.

Digital ear thermometer

Also known as tympanic thermometers, they use an infrared ray to measure the heat that comes from within the ear. May be quicker and easier to use with older children. Not recommended for newborns or babies younger than the three months.



·         Very quick and accurate when placed properly inside the ear.

·         More expensive.

·         Excessive earwax can lead to inaccurate readings.


Digital pacifier thermometer

The baby sucks on it just like a regular pacifier until the device records the peak temperature. Not recommended for newborns or babies younger than the three months.



·         Can take temperature while the child is none-the-wiser.

·         The child needs to hold perfectly still which might a little too much to ask of a baby, especially if it has nasal congestion.

Temporal artery thermometer

Also known as forehead thermometers, they have an infrared scanner that is held over the temporal artery to measure the heat that comes off the head. Suitable for infants older than age 3 months and older children



·         Quick and easily tolerated.

·         May be more expensive.

·         May not be as reliable as digital thermometers.

Plastic temperature strips

Small plastic strips filled with liquid crystals are placed in the forehead where they change color as they record temperature.



·         Easy to use.

·         The surroundings can affect the reading.

·         Not reliable for taking temperatures, in particular for children.

Mercury thermometer

The Commodore Amiga of medical thermometers, this prehistoric artifact consists of mercury encased in a glass tube placed under the tongue, under the armpit, or inside the rectum; body heat makes the mercury rise and where it stops that’s the temperature. Used to be very popular back when Coke had actual coke in it and now fallen from grace for similar reasons; if the glass breaks it could lead to mercury exposure.



·         Nostalgia.

·         Risk of mercury poisoning.

Regardless of the medical thermometer that you choose, remember to follow the instructions included with the product for safe and effective usage.