Reliability of Infrared Thermometers

Angie Szumlinski Studies

Among the many challenges we have faced this year in dealing with the pandemic, screening for the detection of febrile persons entering facilities remains problematic, particularly when paired with CDC and WHO social distancing guidelines. Aggressive source-control measures during the outbreak of COVID-19 have led to the re-purposed use of non-contact infrared thermometry (NCIT) for temperature screening. Fever is defined as either a measured temperature greater than or equal to 100.0° F or subjective fever and symptoms. Respiratory symptoms consistent with COVID-19 are cough, shortness of breath, and sore throat.

A study published in Nature.com aimed to investigate the diagnostic accuracy of temperature measurement using the Fluke 561 Noncontact Infrared Thermometer (NCIT) from a distance of 6 feet. A cursory investigation into this device’s use revealed variable results in temperature measurement, which degraded as a function of distance, and a notable offset compared to the expected body temperature.

The outcomes of this study indicate that a lack of a highly sensitive screening test for COVID-19 undermines efforts to contain viral spread, an issue compounded by imperfect COVID-19 diagnostic tests with low-moderate sensitivities. Appropriate education and training of relevant staff, control of local conditions and environmental factors to reduce measurement error, and the acquisition of an NCIT with improved accuracy may yield improved specificity while also maintaining a 6-foot distance between screening personnel and target individuals. Stay well, stay informed, and stay tuned!