Objective: To evaluate the accuracy and reliability of infrared axillary and aural thermometers in the outpatient setting.
Study design: A prospective observational study of infrared axillary, aural, and digital rectal temperature values from 198 children, aged 3 to 36 months (mean, 1.3 years).
Results: Sensitivity and specificity of the axillary thermometer for rectal fever were 63.5% and 92.6%, respectively (diagnostic accuracy, 83.3%); those for the aural thermometer were 68.3% and 94.8%, respectively (diagnostic accuracy, 86.4%). For all patients, the mean biases of the axillary and aural temperatures were -0.33 degrees F and -0.24 degrees F, respectively. The biases of both thermometers' measurements were significantly correlated with rectal temperature (P <.02); thus, as rectal temperature increased, the accuracy of the compared axillary and aural temperature decreased. Underestimation of rectal temperature was greatest among febrile 1- to 3-year-old children (axillary bias, -1.20; aural bias, -0.36). Age was correlated with an axillary temperature bias (P <.01).
Conclusion: Axillary and aural infrared thermometers were comparable, albeit significantly different than rectal temperature measurements, particularly as the child's age and rectal temperature increased. These thermometers may be useful as noninvasive screening methods in outpatient settings for children who are at least 3 months old, but rectal values should be used for clinical accuracy.