Infrared tympanic thermometers are unreliable in low ambient temperatures

Abstract

AbstractStudy objective To assess the accuracy of infrared emission detection tympanic thermometers at ambient temperatures near and below their specified operating ambient temperature range.Methods In a pilot and subsequent study, two operators, using two brands of infrared emission detection thermometers in ambient temperatures ranging from 24.6°C to −22.1°C measured tympanic temperatures of five healthy male volunteers. Each tympanic temperature measurement was taken twice by each operator, with both thermometers, in both ears of each subject. Results were compared with the subjects’ rectal temperatures taken simultaneously.Results A total of 240 tympanic temperature readings were made. In all ambient temperatures there was close agreement between operators and between left and right ears. With decreasing ambient temperatures there was an increasing and significant difference between rectal and tympanic temperatures. Tympanic temperatures were always lower than rectal readings. Both thermometers only gave warning displays of low ambient temperature when used in ambient temperatures well below their specified operating range. Only one brand continued to give readings at very low ambient temperatures and these were substantially inaccurate.Conclusions Infrared emission detection thermometers have limitations in low ambient temperatures. Operators should be aware of these limitations. Development of models of infrared emission detection devices with a wider operating ambient temperature range may be appropriate for use in the field.