Can Forehead Temperature (FT) be converted to core body temperature?
No, it cannot. There is no scientific equation that describes this relationship. Human beings are too variable for a standard equation of that magnitude.
However, clinically precise measurements are not necessary to detect an individual with an EBT. If there is an individual with an illness that causes them a fever, they will experience a rise in core body temperature. FT will rise as well. If you can detect an above average FT, you can likely detect an individual with EBT.
A small scale Transcat study found that individuals will have a center forehead surface temperature under 94.0 °F if they are not experiencing elevated body temperature (N=10). Participants of this study had an average core body temperature of 98.1 °F (measured with an in-ear tympanic thermometer).
When does someone have an EBT? How can I detect it?
Clinically speaking, an adult has an EBT when their core temperature exceeds 100.4 °F. Please refer to proper medical literature for exact guidance on any temperature values.
The only way in which you can precisely determine an individual’s elevated body temperature is to measure their temperature with a clinical medical device.
EBT can however be detected during a screening process using a handheld Infrared thermometer.
Why would I want to screen EBT from the forehead with a non-contact IR Thermometer?
It is a non-contact process.
It is a quick measurement.
What is the downside of EBT screening with a non-contact IR Thermometer?
It is not a precise measurement.
This is not a clinical device.
Can generate EBT false positives.
How do these handheld IR Forehead Thermometers measure body temperature, and how do I use them?
These types of devices are typically meant to measure the center of your forehead. Always refer to the literature included with your device for exact guidance.
Point the thermometer at the desired area of the forehead and press the measurement button. The thermometer will display a value. Always repeat the measurement if the result seems suspicious.
When initiating the measurement, the device will measure the surface temperature of the skin. This surface measurement will be adjusted by the device to a ‘body’ _temperature. This ‘body’ _temperature is what the device will display. FT will be lower than core body temperature, so the correction will add several degrees.
The device will use an algorithm to do this forehead-to-body adjustment. Different manufacturers and devices will use different algorithms to make these corrections. It is impossible to know every algorithm for every device.