Can You use an infrared thermometer on human?

What is infrared thermometer?

In short, Infrared thermometers is a electronic device which collects the infrared radiated from an object to provide the readings of the object's surface temperature. There are several major components inside the thermometer, a laser emitter for aiming the thermometer at target object, a lens to collect the infrared radiated from the object, a thermopile which induces electrical signal from the collected infrared, a microcontroller captures and processes this signal, and finally a LCD shows the temperature readings. Some infrared thermometers provide memory storage for last time readings, LCD backlight, color indicator, etc. to fulfill different customers expectation. The different combination of the above features make up the infrared thermometer for different application.

What kind of infrared thermometer is used in clinics and hospitals?

There are two main streams of infrared thermometer application in our daily life, the health care application and the general/ industrial application. The main difference between these two applications are the measurable temperature range, laser aiming assistance and the measuring distance between object.

The range of temperature measured by a medical IR thermometer is different from that by an industrial one. Medical infrared thermometer is designed to measure human body temperature, whose accuracy is fine tuned to match the precision requirement in medical application. Normally, the measurable temperature range will be between 32 - 42 degree celsius for a medical infrared thermometer. It is not necessary for a medical thermometer to provide the temperature range far out of human body temperature. In contrast, an industrial grade infrared thermometer can provide a large range of measurable temperature, for example: -50C to 380C. But it should be noted that having such a large measurable temperature range may need to sacrifice the accuracy of the result in return. Industrial/ general grade infrared thermometer with huge measurable tempearture range are normally not recommended to be used to take human body temperature because of its low accuracy. Unless an expensive professional grade may be suitable for this application, the tolerance of industrial/ general purpose thermometer is bigger than that of medical thermometer.

Laser aiming assistance of an infrared thermometer is useful in industrial or general application but not in medical application. Since medical infrared thermometer takes reading by being held 1-2iches in front of a person's forehead. It is not necessary to use a laser beam to target the forehead which is just in front of the thermometer. Also, there is a potential risk that the laser beam will get into the patient's eyes, making the eyes a permanent damage. As a result, medical thermometer will not equip with this feature. When the infrared thermometer is deployed to industrial/ general purpose segment, it is necessary to have this built in laser aiming assistance as this can help to measure the right position as in general situation the targeted location is far more away than 2inches or even it is unreachable. The laser aiming feature is valuable in this scenario. 

Operating distance is another big difference between medical thermometer and the general/ industrial thermometer. As mentioned above, medical infrared forehead thermometer measures human body temprature in about 1-2inches away from the forehead in order to provide an accurate readyings. When it comes to industrial/ general purpose thermometer, they generally can provide a longer distance between the thermometer and the object under measurement. There is a parameter called distance-to-spot ratio which used to determine how far the device should be away from a target. For example, if a distance-to-spot ratio is 12:1, it means the thermometer can measure the temperature of a 1inche diameter spot in a distance of 12inches in order to proivde a reading within a specified tolerance. 

How to take an accurate measurement from Infrared thermometer?

In order to obtain an accurate readings, a proper distance should be maintained when taking the measurement. This is included in the instruction of the device. An incorrect distance will make the reading inaccurate because the distance affects the amount of infrared radiation being captured by the infrared thermometer.  Following the instruction/ user manual of the infrared thermometer is the only way to get an accurate measurement. For more details on tips to use an infrared thermomter is here.

 IN CONCLUSION, it is safe to use any kind of infrared thermometer on human body. For accurate reading on human body temperature, it is recommented to use medical infrared thermometer. For sure, it is no harm to use a general purpose or industrial laser infrared thermometer on human, as long as extra caution is taken when handling the laser beam. As the industrial/ general purpose thermometer is not designed to measure human body temperature, it may not give you an accurate readings. 

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