Performance of axillary and rectal temperature measurement in private pediatric practice

To better understand the role and reliability of axillary temperature measurements in clinical real life, axillary and rectal measurements in infants presenting in a private pediatric practice because of fever were compared. Prospectively, 169 infants (81 girls), median 9 (interquartile range 6–13) months of age, were examined at room temperature (20–24 °C). Two left and two right axillary, as well as two rectal measurements were taken with a digital thermometer and subsequently averaged. The median and interquartile range for axillary and rectal measurements were 36.9 (36.3–37.6) °C and 38.2 (37.4–38.9) °C, respectively (p < 0.0001). The limits of agreement in the Bland-Altman plots were 0.32 to 1.98 °C, with a mean bias of 1.15 °C. Axillary thermometers showed a good sensitivity for detecting rectal temperature > 38 °C (95%) but limited specificity (75%), with an area-under-the-curve of 0.95.