How to correctly use IR forehead thermometers for measuring body temperature?
Are you seeing a lot of IR non-contact forehead thermometers these days? Do you know how to take measurements with them correctly?
01. 12. 2021
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01. 12. 2021
Pay particular attention to:
- Proper preparation of the meter
- The correct selection of the measuring site
- The accurate performance and interpretation of the measurements
- The completion of the measurement and preparation for further work
And remember – if you are not sure about the forehead temperature, it is recommended to use a different way of measuring your body temperature.
The following practical instructions apply to most non-contact frontal human body temperature monitors
Individual monitors may also behave completely differently.
Proper preparation of the IR thermometer
- If the temperature changes significantly, the thermometer will not work accurately, which means that it will show a higher/lower temperature than the actual temperature (error up to 5 °C) or will report an error.
- When moving the thermometer from cold to warm, the lens may become wet and the result will be unusable (the meter normally reports an error).
- Thermometer must be kept at a constant temperature above 10 °C (different for different types and manufacturers). Below 10 °C, most thermometres will not work accurately (they are originally designed to measure at room temperature).
- For proper functioning, thermometer must be at room temperature for at least 15 to 20 minutes before the measurement.
Performing a measurement
- The measurement should always be taken on the same person at the same place on the forehead, as the temperature in the middle of the forehead is usually different from the temperature on the side of the forehead.
- Before taking the measurement, you must remove your hair and any headgear that might obscure the thermometer’s view of your skin (the thermometer measures skin temperature, so it is essential that the sensor can see your skin, as it acts like a camera and records what it sees).
- The measurement should be taken as close to the forehead as possible (1-2 cm). The further you move away, the greater the measurement error and the lower the displayed temperature.
Interpretation of the measurement
- If a person is out in the cold for a long time, the radiant temperature of the forehead (as measured by the meter) decreases by a degree or two, so the measurement is not accurate.
- You can easily check thermometer yourself by rolling up your sleeve and testing it on your forearm (on the arm above the wrist).
- For people who have cream, powder or other similar ointments applied to their forehead, the error in the reading may be a degree or more, meaning that on average a person with ointment on their forehead will have a temperature reading that is lower than the actual temperature.
- For people with a sweaty forehead, the error will be a degree or more, which means that, on average, a person with a sweaty forehead will have a temperature display that is lower than the actual temperature.
- If you are not sure about the forehead temperature, it is recommended to use a different way of measuring the body temperature (in the ear, armpit).
Completion of the measurement in preparation for further work
- Clean thermometer with a soft cloth if necessary, or according to the manufacturers’ recommendations, which mostly recommend alcohol-based cleaners.
- The thermometer lens should also be cleaned regularly. The use of cotton buds and at least 70 % alcohol is recommended. Care must be taken to avoid leaving fibres, other particles or cleaning agent residues on the lens.
- After cleaning, it is necessary to wait until the alcohol completely evaporates.
- After use, put thermometer away, otherwise it will heat up unnecessarily and there will be a difference in temperature between the meter and the surrounding area, which will cause display errors.
Correct use of IR thermometers