Common types of thermometers and how to use them

This article was professionally consulted by Specialist Doctor II Dinh Van Loc - Anesthesiologist - Department of General Surgery - Vinmec Danang International General Hospital. The doctor has more than 23 years of experience in anesthesia and resuscitation.

Thermometers are the most commonly used medical instruments today. On the market, thermometers are sold with many different models and uses, including specially designed baby thermometers. Every household should buy themselves good thermometers and understand how to use them to protect the health of themselves and their loved ones.

Mercury thermometer is the oldest type of thermometer and is also the most used type in medical facilities in our country. The temperature measurement location chosen when using a mercury thermometer is the armpit, which gives an approximate result of the internal body temperature. When using, the thermometer should be clamped firmly in the armpit pit so that the tip of the thermometer is in full contact with the skin at the top of the armpit.
Remember to dry your armpits and shake the thermometer to lower the mercury column below 35.5 degrees Celsius. Results are read after at least 5 minutes of measurement. The exact body temperature is obtained by adding 0.5 degrees Celsius to the measured result. A mercury thermometer can also be used to take an rectal temperature. Before measuring, it is necessary to lubricate the thermometer tip, then push the tip of the thermometer into the anus, about 2-3 cm, read the result after about 3 minutes.

The outstanding advantage of mercury thermometers is accurate results. However, with complicated measuring practices, mercury thermometers are not easy to use for everyone, especially infants and young children. Clamping the thermometer in place in the middle of the axillary fossa continuously for 5 minutes is difficult to do in children. A common accident when using mercury thermometers is thermometer breakage. Mercury inside is released to the outside, which can cause poisoning for users. Handling and cleaning up mercury spills is a must-have skill for those who use mercury thermometers. A few things to remember when handling broken thermometers are as follows:
Remove soiled clothing, and wash hands with soap Turn off fans and air conditioners to reduce evaporating mercury Wear gloves when collecting particles mercury, absolutely do not use your bare hands Use wet cotton to wipe mercury particles into a glass jar with a tight-fitting lid If there are signs of mercury poisoning, immediately seek medical attention. timely treatment.

Electronic thermometers operate on the basis of heat induction in the areas in contact with the thermometer tip. Depending on the location of body temperature measurement in the mouth, armpit, anus or ear, electronic thermometers are designed with different shapes.
The most commonly used temperature measurement location is the armpit because of its convenience and ease of holding the thermometer. However, a surprising thing is that the anus is the most accurate body temperature measurement location, instead of the armpit as many people mistakenly believe. Thermometers for infants and children under 3 years of age are often designed to suit the location of temperature measurement in the anal area. After measuring, it is necessary to clean the thermometer for future use. In contrast, electronic thermometers used for older children and adults are often used to measure oral temperature. At that time, the thermometer tip should be placed under the tongue and the person being measured should keep the mouth closed. Only take the temperature in the mouth about 15 minutes after eating to limit errors. Note, do not use an oral thermometer to measure the rectal temperature and vice versa.

Currently, on the market, there are electronic thermometers for babies that are used to measure oral temperature. These types of electronic thermometers have a nipple shape to deceive children, young children do not realize that a temperature measurement is being conducted, so they do not cry and the measured temperature is more accurate and objective. However, this type of thermometer with a special design is not necessarily considered one of the good thermometers because it gives inaccurate results like others and takes many minutes to read.
Compared with mercury thermometers, electronic thermometers were born later but are used more and more widely. The time it takes to get a body temperature reading when using an electronic thermometer is only about a minute, shorter than when using a mercury thermometer. Electronic thermometers are safer, and are suitable for people of all ages, including infants, children and the elderly. Many studies have shown that body temperature measured by electronic thermometers is not significantly different from mercury thermometers.

Infrared thermometer is the type of thermometer that takes the least time to measure, only about 3 seconds. This type of thermometer is usually used to measure the temperature of the ears and forehead.

The infrared thermometer for measuring temperature in the ear can be used for all subjects, especially children over 6 months old, without causing fussiness because it does not cause discomfort. This type of infrared thermometer is not recommended for use in infants and the readings are affected in the presence of earwax. When measuring, just insert the thermometer tip into the ear canal and press the measurement button, the result will be displayed after a few seconds.
Infrared forehead thermometers are usually placed in the corresponding temporal artery. Bring the thermometer in contact with the center of the forehead and slide the thermometer outward towards the temples to find the highest temperature peak. The measurement time is very fast, within a few seconds and gives an accurate temperature equivalent to an electronic rectal thermometer. The relatively high cost is the only drawback of this thermometer.