Comparability of tympanic and oral mercury thermometers at high ambient temperatures.

Background: Body temperature can be measured in seconds with tympanic thermometers as opposed to minutes with mercury ones. The aim of this study was to compare tympanic and oral mercury thermometer measurements under high ambient field temperatures.

Results: Tympanic temperature (measured thrice by 3 operators) was compared to oral temperature measured once with a mercury-in-glass thermometer in 201 patients (aged ≥5 years), on the Thai-Myanmar border. Ambient temperature was measured with an electronic thermo-hygrometer. Participants had a mean [min-max] age of 27 [5-60] years and 42% (84) were febrile by oral thermometer. The mean difference in the mercury and tympanic temperature measurement for all observers/devices was 0.09 (95%CI 0.07-0.12)°C and intra-class correlation for repeat tympanic measurements was high (≥0.97) for each observer. Deviations in tympanic temperatures were not related to ambient temperature.

Conclusion: Clinically significant differences were not observed between oral and tympanic temperature measurements at high ambient temperatures in a rural tropical setting.