Hi Dustcap, In this review: Non-Contact Thermometers for Detecting Fever: A Review of Clinical Effectiveness the Exergen and Thermofocus were two of the devices used to measure skin temperature.

In the summary of findings, with regard to the accuracy of thermal scanners for detecting febrile individuals, four studies expressed conclusions in favor of the utilization of thermal scanners for fever detection,(10,13,22,24) whereas one study stated that this type of device is unsuitable for this purpose due to a high proportion of false positives.(11)

Ultimately, non-contact measurement is not as accurate as in ear, skin probe, or rectal measurement, but is safer under current covid circumstances, and fine for the majority of patients. Surface measurement would be used in the most seriously ill patient, and non-contact measurement is also the simplest way to 'covid screen' patients, staff, and visitors.