Comparison of forehead temperature screening with infra-red thermometer and thermal imaging scanner

This observational study aimed to compare forehand temperature values concomitantly measured with an infrared thermometer and a thermal imagine scanner. The study population consisted of 24 consecutive healthcare workers (16 women and 8 men; mean age: 42±14 years, range 19-65 years), undergoing routine forehand temperature scanning before entering the hospital building at the University Hospital of Verona (Verona, Italy). The forehand temperature measurement was first repeated 10 times on the same subject with the same thermal imagine scanner (Hikvision DS-2TD1217B-6/PA), and immediately afterwards was repeated 10 additional times on the same subject with the same infrared thermometer (Jumper JPD-FR300). The mean imprecision of forehand temperature measurement was 0.6±0.3% for the infrared thermometer and 0.2±0.1% for the thermal imagine scanner, respectively. The correlation between values obtained with the two devices did not reach statistical significance (r=0.19; p=0.382), and values recorded with the infrared thermometer (36.2±0.4 °C) were slightly but significantly higher than measured with the thermal imagine scanner (36.0±0.2 °C; p=0.034). The infrared thermometer tended to underestimate forehand temperature <36 °C (mean bias, -0.3 °C; p=0.008), while it significantly overestimated values above this threshold (mean bias, 0.4 °C; p<0.001). In conclusion, despite cumulative imprecision was <1%, precision of thermal imagine scanner was better than that of the infrared thermometer. Moreover, these two forehand temperature detectors could not be used interchangeably for systematic monitoring the body temperature.