Accuracy of a Noninvasive Temporal Artery Thermometer for Use in Infants

OBJECTIVES: To assess the accuracy of a new noninvasive temporal artery (TA) thermometer in infants; to compare the accuracy of the TA thermometer with that of a tympanic thermometer, using rectal thermometry as the criterion standard; and to compare the tolerability of the TA thermometer with that of the tympanic and rectal thermometers. DESIGN: Prospective evaluation of the accuracy of TA and tympanic thermometry, using rectal thermometry as the criterion standard. SETTING: Emergency department of an urban pediatric hospital. SUBJECTS: Convenience sample of 304 infants younger than 1 year presenting for care. MAIN OUTCOME MEASURES: Temperatures were measured using TA, tympanic, and rectal thermometers for all infants. Agreement between TA or tympanic and rectal temperatures was assessed. The sensitivity and specificity of TA or tympanic thermometers for detecting rectal fever were determined. Discomfort scores, using a standardized scale, were assessed by trained observers after each temperature measurement was made. RESULTS: Linear regression analysis of the relation between TA and rectal temperatures yielded a model with a slope of 0.79 (vs a slope of 0.68 for tympanic vs rectal temperature; P =.02) and an r of 0.83 (vs r = 0.75 for tympanic vs rectal temperature; P<.001). Among 109 patients with a rectal temperature of 38 degrees C or higher, the TA thermometer had a sensitivity of 0.66 compared with the tympanic thermometer's sensitivity of 0.49 (P<.001). Discomfort scores with TA thermometry were significantly lower than with rectal thermometry (P =.007). CONCLUSIONS: The TA thermometer has limited sensitivity for detecting cases of rectal fever in infants. However, the TA thermometer is more accurate than the tympanic thermometer in infants, and it is better tolerated by infants than rectal thermometry.