Medical equipment

Types of Thermometers and Their Accuracy

A thermometer is an essential element of a home’s medicine cabinet. Since it can easily measure the body’s temperature, it will enable you to quickly check if someone in your family has fever. This, in turn, can help you decide what’s the best treatment for the condition, for example, if medication for fever should be added on top of cold and flu medications. But with the range of thermometers available on the market, how do you know which one provides the most reliable measurements?

Like with other devices, it’s important to understand how different thermometers work to determine which one is best for you. Not all thermometers work the same way or are designed to provide the same temperature reading. When someone in your family is sick, guessing is the last thing you want to rely on. Here is what you need to know about the different types of thermometers, how to use them and what their measurements mean.

Infrared Thermometer

Commonly known as forehead thermometers, these devices use infrared technology to produce accurate temperature readings. It is a non-contact thermometer in which readings are obtained by simple point ting the thermometer at the forehead from a distance of between 3-5 centimetres. The device takes the body temperature by reading the infrared waves emitted by the temporal artery, which is located just below the skin on the forehead. The temperature is shown on a backlit display screen, which displays the temperature reading in larger numbers, which makes reading the temperature very easy, even if in a darkened room. 

One of the greatest benefits of this thermometer is that it gives an almost instantaneous reading and it also comes with a built-in fever alarm to indicate if a temperature is very high. The thermometer can be used immediately, which can be handy if two persons in your home are sick at the same time. Some infrared thermometers can store previous readings, making it easy to check on the progress of the patient. 

infrared thermometer

Wondering is forehead thermometer more accurate? Research has found that forehead thermometers are very accurate, more than tympanic or auxiliary temperature readings. They’re also more convenient and hygienic than other types of thermometers available. An infrared thermometer can be used at any time on any person, even if they’re sleeping. And because the thermometer doesn’t come into contact with the skin, the risk of cross-infection is minimized. This means, there is no need to have separate thermometers for each person in the family. 

Some infrared thermometers can even be used to measure the temperature of baby food, so you can prevent feeding your child with too hot formula or food. It can also be used to measure the temperature of bathwater. 

forehead thermometers

Digital Stick Thermometers

Before the invention of forehead thermometers, digital stick thermometers were one of the most frequently used pieces of diagnostic equipment, both in homes and medical settings. These thermometers read the temperature through direct contact with the inside of the mouth or rectum. Some benefits of using this kind of thermometer are fast readings (less than a minute), ease of use, a budget-friendly option and others. 

However, these thermometers are not the ideal solutions in some situations. For example, in a fast-paced environment where a person needs to take many temperatures in a row, the results of a digital stick thermometer may not be fast enough to keep the line moving. And because the thermometer needs to get into direct contact with the mouth or rectum, it’s not possible to use it with multiple patients without proper probe covers or sheats, which can add to the cost of care. 

Digital Ear Thermometers

Digital ear thermometers also use infrared technology to provide a fast and accurate reading. They measure the thermal radiation emitted by the eardrum. One great thing about these thermometers is the ability to use replaceable disposable covers instead of having to use alcohol to disinfect the tip of the thermometer each time it is used, like with touch thermometers. 

The downside of these thermometers is that measurements can be affected by an error, for example, due to retention of earwax which can obscure the eardrum. In this case, it’s necessary to clean the auditory canal, lightly tighten the visible part of the ear and direct the tip directly to the surface of the eardrum. 


If you are wondering if is an ear or forehead thermometer better, ear thermometers tend to be less accurate. The measurement error is ± 0.2° C. Error can also occur when the ambient temperature exceeds the room temperature range of 18 to 26° C. 

Disposable Strip Thermometers

These thermometers come in the form of a plastic strip, in which the recesses are stamped at the same intervals. In each of the recesses, there is a mixture of substances that change colour depending on the temperature. In order to obtain an accurate temperature reading and to avoid the contact of a thermally sensitive substance with the surrounding, the cavities of the strips are covered with a transparent polymer. Disposable strip thermometers can measure the temperature of the forehead, under the armpit or in the mouth. 

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