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Tympanic thermometers, or digital ear thermometers, use an infrared sensor to measure the temperature inside the ear canal and can give results within seconds. If a person uses it correctly, the results will be accurate. However, ear thermometers may not be as accurate as contact ones.

Ear thermometers are noninvasive, hygienic, quick, and easy to use. Children may also find them more comfortable.

Ear thermometers are available for purchase in pharmacies, grocery stores, medical supply stores, and online.

This article discusses ear thermometers, their accuracy, how to use them, and alternative methods for taking a temperature.

A digital ear thermometer.Share on Pinterest
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Digital ear thermometers measure the temperature of the tympanic membrane, or eardrum, through an infrared sensor.

According to the United Kingdom’s National Health Service (NHS), if a healthcare professional takes a person’s temperature via the ear in a hospital setting, it can give an accurate reflection of the person’s core temperature.

However, the following can lead to incorrect readings:

  • improper positioning
  • the size and length of the ear canal
  • lying on the ear beforehand
  • the presence of earwax
  • moisture in the ear

Rectal thermometers, which measure the temperature in the bottom, provide the most accurate readings for infants and toddlers up to 3 years of age.

To use an ear thermometer, follow these steps:

  1. Pull the top of the earlobe up and back.
  2. Gently insert the tip of the thermometer into the ear canal toward the eardrum. The sensor should be pointing down the ear canal and not at the wall of the ear.
  3. Once the thermometer is in position, turn it on and wait for it to signal that the reading is complete.
  4. Remove the thermometer and read the temperature.

It is important to use a clean probe tip each time and to follow the manufacturer’s instructions.

Body temperature can vary depending on different factors, such as a person’s age, their environment, and the time of day. For example, body temperature is lower in the mornings and higher in the evenings.

The average body temperature for an adult is 98.6°F (37°C). However, this can range anywhere from 97.7ºF (36.5ºC) to 99.5ºF (37.5ºC).

A fever occurs when the body temperature rises above 100.4°F (38°C) for an extended period of time.

When an ear thermometer is in a proper position, it is a comfortable option for both children and adults.

However, it is not advisable to use an ear thermometer on infants who are 6 months old or younger.

Additionally, a person should not use an ear thermometer if they:

  • use prescription ear drops or other in-ear medications
  • produce excess earwax
  • have an outer ear infection
  • have blood or other fluid in the ear
  • have a sore ear
  • have recently had an ear surgery

The most common methods of temperature assessment include:

  • Electronic digital thermometers: These measure oral, axillary, and rectal temperatures. Axillary means that a person takes a temperature under the arm.
  • Basal thermometers: These are digital thermometers that measure basal body temperature, which is the temperature of the body at rest. Healthcare professionals often use basal body temperature as a way to predict fertility or as a supplemental method of birth control.
  • Temporal artery thermometers: Forehead thermometers, or temporal artery thermometers, use an infrared scanner to measure the temperature of the temporal artery under the skin of a person’s forehead.
  • Liquid crystal forehead temperature strips: These contain tiny liquid crystals and chemical compounds that change color as they react to the temperature of the skin. Although these strips are painless and disposable, the readings they provide are often inaccurate.

People should avoid using glass mercury thermometers as they can be dangerous.

The Environmental Protection Agency (EPA) notes that there is a ban on the retail sale of mercury thermometers in at least 13 states.

In addition to a high temperature, people with a fever may experience some of the following:

The NHS notes that it is necessary to contact a healthcare professional if a person is:

  • under 3 months old and has a temperature of 100.4ºF (38°C) or higher
  • 3–6 months old and has a temperature of 102.2ºF (39°C) or higher
  • experiencing other symptoms, such as a rash

Additionally, a person should contact a doctor if the fever has lasted for 5 or more days or has not reduced after they have taken acetaminophen.

A person should seek emergency medical attention if they develop any of the following symptoms:

Learn more about average body temperatures and when a person should seek medical help here.

A tympanic thermometer, or ear thermometer, is a hand-held device that measures the temperature of the eardrum using an infrared sensor. Tympanic thermometers are available at most grocery, drug, and medical supply stores.

As they are noninvasive, ear thermometers are a popular option for parents of young children. However, improper placement and excess earwax, for example, may lead to inaccurate readings.

People should not use an ear thermometer on infants who are 6 months old or younger.