Axillary Thermometry Demonstrates Greater Reliability Compared With Rectal Thermometry in Healthy Neonates

Rectal thermometry (RT) is considered the gold standard for measuring temperature in newborns, despite increasing use of temporal artery thermometry (TT) and axillary thermometry (AT) methods. Few prospective studies compare RT, TT, and AT in a newborn nursery setting. To determine the accuracy and reliability of these methods, we enrolled 205 healthy, full-term newborns. TT displayed higher mean temperatures than RT by 0.25 °F (standard error [SE] = 0.04, P < .001). AT and RT measurements did not significantly differ, with their means differing only by 0.02 °F (SE = 0.04, P = .87). For reliability, RT measurements differed by 0.45 °F (SE = 0.03) in either direction of the models’ predicted mean for each subject. AT and TT measurements varied much less from their predicted means 0.32 °F (SE = 0.02) and 0.34 °F (SE = 0.02), respectively (both P < .001). Assuming mean RT is correct, TT is less accurate than AT. RT showed poor reliability between measurements. AT is an accurate and reliable method of temperature screening in healthy neonates.