Measuring the face or forehead temperature is not sufficient when using thermal imaging for elevated body temperature (EBT) monitoring. The measurements at the face and forehead provide inconsistent results and measurements are typically several degrees below actual body temperature. It is critical to measure the temperature at the inner corner of the eye. 


Please see previous articles here for more detailed information. 

The images on this page are not captured in line with ISO 13154 best practice procedures. However, as the purpose of the comparison is relative temperature variance vs absolute temperature variance, the results are valid.

Thermal images of 10 different people were captured. We acknowledge the small sample size and intend to conduct a more extensive trial. However, these results align with results in prior literature and are provided for illustrative purposes.  

We compared the maximum temperature measurement at the forehead vs the temperature measurement at the medial canthus (inner corner of the eye).

The average difference in measured temperature between the forehead and canthus was 1.3°C.

More importantly, the difference in temperature was not consistent and ranged from 0.9°C to as much as 2.2°C. This means that the lower temperature readings at the forehead cannot be corrected for by a simple offset correction.

This summary is a clear reminder of why thermal imaging screening guidelines exist. ISO 13154 was written based on experience from the SARS and MERS coronavirus outbreaks. It is not an abstract, theoretical document - it provides an important set of guidelines that should be considered by anyone who is planning to utilise thermal imaging for fever screening in their organisation.