There are a few varieties of thermometers available to measure body temperature. In the past, most people used an oral or rectal thermometer. More recently, infrared ear thermometers have been used in medical facilities and are available for home use.
An ear thermometer works by measuring the heat released from the eardrum in the inner ear. The heat that is emitted from the membrane of the eardrum is measured by an infrared detector on the ear thermometer and a digital readout is given. Almost all ear thermometers use infrared detectors.
Body temperature is most accurately measured when it is taken in a spot recessed in the body. This is why taking a temperature under the tongue or in the rectum works well. The eardrum is considered a good location because it is located deep in the head.
Most ear thermometers have a short tube connected to the rest of the device. The tube is placed into the ear canal and a button is pushed. The infrared sensor detects the heat from inside the ear within seconds. The temperature reading is then displayed on a digital screen on the ear thermometer.
Ear thermometers work best in babies over the age of one. Very young babies have small ear canals and it may be harder to get the correct alignment into the canal. Most babies, over the age of one year, will have large enough ear canals for the ear thermometer to work effectively.
Studies on ear thermometer accuracy vary. Most manufactures claim they are accurate within 0.5 degrees when used correctly. Proper alignment into the ear canal is essential for the most accurate results. Manufactures recommend pulling outward, slightly above the ear lobe, while putting in the thermometer. This will lengthen and straighten out the ear canal and help with proper alignment.
There are a few things which can get in the way of an accurate reading. Ears should be clean when using the thermometer, since a buildup of ear wax may contribute to an inaccurate reading. The cold air from the outside can also hinder the infrared heat reading of the eardrum. Waiting 15 minutes after being out in the cold is suggested.
Caution should also be used when using the ear thermometer. The eardrum is delicate and pushing the thermometer too far into the ear can cause damage. However, not putting the device far enough into the ear may prevent an accurate temperature from being detected.
Most pharmacies, department stores and medical supply stores will carry a variety of ear thermometers. They can also be purchased online. The cost varies. However, most which are intended for home use, are priced around $50 US Dollars (USD).