Realizing the difference between skin temperature and a raised body temperature caused by fever is a key first step towards implementing a non-contact screening solution. Using thermal imaging cameras to detect elevated skin temperatures helps industrial spaces, government facilities, and small businesses safeguard the health of employees and visitors. Understanding the purpose of elevated skin temperature screening, recognizing its limitations, and capturing accurate measurements are elemental in returning to work safely.
COVID-19 and other viral diseases often trigger fever in humans, which raises body temperature as an immune response to infection. While all fevers elevate body temperature, not all increases in body temperature are due to an immune response. Body temperatures vary person to person and are easily influenced by physical activity, warm weather, and medication. While anticipating these variations is important, elevated body temperature remains one of the more telling signs that an individual may be fighting infection. When it comes to accurately measuring body temperature for medical purposes, a dedicated medical device, such as an internal thermometer, is required.
Skin temperature is primarily influenced by body temperature and is one of the most accessible indicators of an immune response. Like body temperature, skin temperature is influenced by environmental temperature, physical activity, and circulation. Infrared technology makes non-contact, socially-distanced skin temperature screening possible. Under the right conditions, thermal screening for elevated skin temperature is a fast, safe method to detect individuals that may be experiencing an abnormally high body temperature or fever.
Despite the environmental and individual factors that can influence skin temperature, it is possible to obtain an accurate measurement when using recommended tools and procedures. There are several factors that influence the accuracy of skin temperature screening with thermal imaging. Assuming your camera is fit for the job and equipped with proper screening software, one of the most important details for accurate skin temperature measurements is to focus on the corner of the eye. While the forehead is easier to quickly screen, it is more susceptible to environmental interferences and more likely to generate measurement errors. Research has shown that the corner of the eye—the region medially adjacent to the inner canthus—provides a more accurate estimate of core body temperature than other areas of skin. This is because skin at the canthi is thin (decreasing insulating effects), is less exposed to environmental factors, and is directly over major arteries which increase blood flow and heat transfer.