How to Read a Thermometer – Ultimate Guide

The COVID-19 epidemic has spread to the world. How to determine if you are infected? According to the 10 main symptoms announced by the World Health Organization, fever is the most common symptom, and 87.9% of infected people are under high body temperature.

As soon as this report came out, every household began to buy thermometers. However, there are all kinds of thermometers on the market, which one should we choose and how to read a thermometer? Fortunately, this post will introduce the types of thermometers and their respective instructions.


how to read a thermometer

Types of Thermometers


A thermometer is a device used to measure body temperature. At present, thermometers can be roughly divided into three categories: mercury thermometers, electronic thermometers, and infrared thermometers.


1. Mercury Thermometer


Mercury thermometer is a kind of expansion thermometer. Almost everyone knows that it is cheap, easy to use, and easy to disinfect. However, the disadvantages cannot be ignored, including the long measurement time, the glass material is easy to break, and once broken, the mercury will pollute the environment and endanger health.


Mercury Thermometer


2. Electronic Thermometer


Compared with mercury thermometers, electronic thermometers have the advantages of no mercury, convenient reading, short measurement time, high measurement accuracy, and buzzer prompts. However, the display accuracy of the electronic thermometer is affected by factors such as electronic components and battery power.


digital thermometer


3. Infrared Thermometer


An infrared thermometer is a measuring meter that uses the principle of radiation to measure human body temperature. Its main advantages are that it is very simple and convenient to use, and can avoid cross-infection. However, Infrared thermometers are relatively expensive and easily affected by ambient temperature.

Infrared thermometers are mainly divided into contact infrared thermometers (ear thermometers) and non-contact infrared thermometers (forehead thermometers).


Ear thermometers

Ear thermometers use the infrared spectrum emitted by the eardrum to determine body temperature. Infants under 6 months, patients with otitis externa and otitis media, and those who wet their ears after swimming or bathing are not suitable for ear thermometers.


ear thermometer


Forehead thermometers

A forehead thermometer is an instrument designed for measuring the forehead temperature of the human body. In an ideal state, the measurement result should be accurate, but there are many influencing factors, such as room temperature and dryness of the skin, which will affect the result.


Forehead thermometers

How to Use Different Thermometers to Measure Temperature?

Three types of thermometers are described in detail above. Now, let’s learn how to use them to measure temperature. Please bear in mind that do not exercise vigorously before the measurement. And no matter which thermometer you choose, wipe it with alcohol cotton and dry it before use.


Using a Mercury Thermometer


Mercury thermometer is one of the most common thermometers. We usually measure body temperature in 3 places, namely the mouth, armpit, and anus. However, it is not recommended to put it into the mouth or anus because it can easily break and cause damage and mercury leakage. Therefore, the following just show you how to measure the temperature under armpits.

1.Before using, make sure that the temperature of the thermometer is close to the minimum temperature.

2.Place the metal tip of the thermometer under the armpit.

3.Clamp it with your upper arm to prevent it from dislocating or falling.

4.Wait 5 minutes, and then remove the thermometer from the armpit.

5.Observe the position where the liquid ends. This position will be the measured temperature value.

Note: Be careful not to touch the metal head with your hands.


Using an Electronic Thermometer


The measurement method of using an electronic thermometer can also be divided into three types, oral temperature, axillary temperature, and rectal temperature. There are some differences between these methods. Check the details below.


Method 1. Oral

Place the measuring end of the thermometer under the tongue. Close your lips tightly and fix the position by a hand. Take a reading after measuring 3-5 minutes. After reading the value, it can be disinfected again to ensure the safety of the next use.

Note: Do not eat anything 30 minutes before the measurement.

Method 2. Axillary

Place the measuring end under the armpit, and clamp the thermometer with your upper arm to prevent it from dislocating or falling. Wait for 5-10 minutes and take out the thermometer. After reading the temperature data, wipe the thermometer with alcohol cotton for the next use.

Tip: Do not take a bath before measuring.

Method 3. Rectal

Lubricate the measuring end of the electronic thermometer with lubricant (Vaseline or paraffin oil). Open the anus with the hand, rotate the anal table, and slowly and gently insert it. After 1-3 minutes, take out the rectal meter, wipe the thermometer clean with toilet paper, and then read the temperature data. After reading the temperature, disinfect with alcohol cotton pads.

Note: The insertion depth is 1.25 cm for infants; 2.5 cm for children; 3.5 cm for adults. If the thermometer is inserted incorrectly, the measurer will feel uncomfortable and even painful.

Among the above three methods of measuring temperature, the rectal body temperature is the closest to the internal body temperature, so it is the most accurate.



Using an Infrared Thermometer


At present, the common infrared thermometers on the market mainly include ear thermometers and forehead thermometers. Below are the specific steps and precautions when using them.


Ear Thermometer:


1.Install a brand new, clean earmuff.

2.Turn on the power button, and wait the Ready symbol appears.

3.Fix the head (with the face facing side and ears facing up).

4.Keep the ear canal very straight. For infants under one-year-old, pull the ears backward, and for children and adults over one-year-old, pull the ears upwards and backward.

5.Insert the probe into the ear canal and close it tightly to ensure the correct temperature of the eardrum is measured.

6.Press the temperature measurement key, and the measurement ends after the beep.

7.Remove the probe from the ear canal, and the temperature value is displayed on the screen.

Note: Before use, make sure the ear canal is clean.


how to read a thermometer

Forehead Thermometer:


1.Turn on the forehead thermometer.

2.Switch to the body temperature mode, if needed.

3.Pull away the hair and wipe off the sweat to make sure that there is no obstruction on the forehead.

4.Align the forehead thermometer at the center of the forehead and keep a distance of 3-5cm.

5.Press the measurement button, and check the body temperature.

Note: When outdoors, it is more accurate to measure the parts covered by clothes, such as the wrists and neck. It is recommended to take 3 times during the measurement and use the average body temperature.


how to read a thermometer

How to Clean and Store Different Thermometers?


The types of thermometers and how to read a thermometer are detailed above. This part will focus on the cleaning and storage methods of different thermometers.

Mercury thermometers: The highest temperature value of the mercury thermometer is 42°C. During storage or cleaning, the temperature must not exceed 42°C. Besides, mercury thermometers are easily broken. Once broken, the mercury flowing out will pollute the environment and be harmful to health. Therefore, it must be properly stored and handled carefully.

Electronic thermometers: Use medical alcohol to disinfect the electronic thermometer when cleaning. After disinfection, wipe the liquid dry with a paper towel. Put the digital thermometer in the storage box provided. Do not drop the electric thermometer. Electronic thermometers are not shock-proof products.

Infrared thermometers: The service life of an infrared thermometer is usually about five years. The maintenance is directly related to the measurement performance of the instrument. The surface of the instrument, especially the surface of the infrared sight should be cleaned regularly with alcohol cotton.


What Is a Normal Body Temperature?


The standard of normal body temperature is based on the value of most people, not the absolute value of the individual. The normal value of oral temperature is 36.3℃ - 37.2℃ (97.34℉~98.96℉), the normal value of axillary temperature is 36℃ - 37℃ (96.8 ℉~98.6℉), and the normal value of rectal temperature is 36.5℃ - 37.7℃ (97.7℉~99.86℉).

There are differences in body temperature between morning and evening, various parts of the human body, and between men and women. The normal body temperature of the human body has a relatively stable range, but it is not constant. If you really want to know if you have a fever, you should measure your body temperature frequently to find out abnormal changes.



digital thermometer




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    Thanks, Helps a lot

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