Forehead, Temple and Wrist Temperature Assessment of Ethnic Groups using Infrared Technology

Abstract

Non-contact infrared sensors are widely used as a diagnostic tool for elevated body temperature during initial screening for coronaviruses. The aim of this study was to investigate the thermal differences at three anatomical points: temple, forehead, and wrist, in the initial screening for temperature indicative of febrile and non-febrile states in skin pigmentation variations in Black, Half-Black and Caucasian skins, correlated with height and weight variables. Temperatures were obtained by means of an infrared thermometer in 289 volunteers with mean age of 18.30 ± 0.76, in a controlled environment according to Singapore Standard, SS582 part 1 and 2, normative standard IEC 80601-2-59, with standard technical protocols established by the International Organization for Standardization, ISO / TR 13154. The data were processed in MATLAB® R2021a, and data normality verified by Kolmogorov-Smirnov test, non-parametric data paired between temple / forehead / wrist were compared using the Wilcoxon signed-rank test. The results show different median temperatures in these anatomical regions, 37.2°C at the temple, 36.8°C at the forehead and 36.4°C at the wrist. As the temple region presents a temperature higher than the other investigated regions and, therefore, close to the core temperature, it should be considered for the initial screening of SARS-CoV-2 when using non-contact infrared thermometers. Furthermore, no significant changes were found due to variation in skin tone, height, or weight.

Keywords: Black; Body temperature; COVID-19; Half-Black; and Caucasian skins; non-contact infrared thermometer; screening temperature protocol.

Fig. 1

Facial arteries (a); thermographic image, front view (b), anatomical position of the superficial temporal artery (c); thermographic image, side view (d). The target point is marked as a circumference on images b) and d).

Fig. 2

Schematic targeting point in the wrist region, radial styloid process and the radial artery, palmar ramus (a); thermographic image (b). The target point is marked as a circumference on image b).

Fig. 3

Setup of thermal data acquisition in different body regions: temple (a), forehead (b), wrist (c)

Fig. 4

Body median temperature measurements at the three regions

Fig. 5

Average temperature data correlated with body weight data.

Fig. 6

Average temperature data correlated with height data.

Fig. 7

Temperature data correlated with ethnicity data.

Fig. 8

Effect size data. The left graph includes all volunteers; while in the right is separated by ethnic group, Ca. – Caucasian, Bk. - Black, HB. – Half Black.