Forehead or ear temperature measurement cannot replace rectal measurements, except for screening purposes

BACKGROUND: Measuring rectal temperature in children is the gold standard, but ear or forehead measures are less traumatic and faster. The quality of non-invasive devices has improved but concerns remain whether they are reliable enough to substitute rectal thermometers. The aim was to evaluate in a real-life children population whether the forehead or ear temperature measurements could be used in screening to detect fever and if the agreement with the rectal temperature for different age groups is acceptable for clinical use. METHODS: Cross-sectional clinical study comparing temporal and tympanic temperatures to rectal temperature in 0–18-year-old children. The ear thermometer was a Pro 4000 Thermoscan, the temporal Exergen TAT. Rectal temperature ≥ 38.0 °C was defined as fever. RESULTS: Among 995 children, 39% had a fever. The ear thermometer had a significantly greater ability to detect fever than the temporal thermometer (AUC 0.972; 95% CI: 0.963–0.981 versus AUC 0.931; 95% CI: 0.915–0.947, p < 0.0001). Both devices had the lowest sensitivity in the youngest and oldest children, and only the ear thermometer reached a sensitivity above 90% in the 0.5–5-year age group. The Bland-Altman analysis showed that the 95% limits of agreement for the temporal thermometer was between − 1.2 to + 1.5 °C and for the ear thermometer between − 0.97 to + 1.07 °C. CONCLUSIONS: Based on a large sample of children, the temporal measurement of temperature is not currently recommendable, but with the technology used in this study the ear measurement proved useful for screening purposes, especially among children aged 6 months to 5 years. For the exact measurement of temperature, the rectal method is still recommended. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12887-018-0994-1) contains supplementary material, which is available to authorized users.