Surface Temperature Scanners are Unreliable Fever Detectors

Infrared thermographic screening for Covid‐19 and other febrile infections can result in a large number of false negatives, according to a new study.

Researchers at the University of Portsmouth (United Kingdom) and Jozef Stefan Institute (Ljubljana, Slovenia) conducted a review of literature regarding infrared (IR) thermometers and found that different IR thermometers give different results varying by as much as 2° C, and that more than 80% people tested using IR thermography can give a false negative result, due to a myriad of reasons, such as ambient temperature, infections, sunburn, exercise, and blood pressure. In addition, measuring skin temperature does not give an accurate estimation of deep body temperature.


The researchers suggest therefor, that as a direct measure of deep body temperature is impractical out of the hospital setting, and is also more expensive, overly invasive, and too time consuming for practical widespread use, taking two temperature measurements, one of the finger and the other of the eye, is likely to be a better and more reliable indicator of a fever-induced increase in deep body temperature. The study was published on January 21, 2021, in Experimental Physiology.

“If scanners are not giving an accurate reading, we run the risk of falsely excluding people from places they may want, or need, to go, and we also risk allowing people with the virus to spread the undetected infection they have,” said senior author Professor Michael Tipton, PhD, of the University of Portsmouth. “The pandemic has had a devastating global effect on all aspects of our lives, and unfortunately, it’s unlikely to be the last pandemic we face. It’s critical we develop a method of gauging if an individual has a fever that’s accurate and fast.”

The most common and widespread symptom of COVID-19 is a fever, followed by loss of taste and smell and a host of other symptoms, including dry cough, sputum production, shortness of breath, muscle or joint pain, sore throat, headache chills, nausea or vomiting, nasal congestion, and diarrhea.

Related Links:
University of Portsmouth
Jozef Stefan Institute