Threshold for defining fever varies with age, especially in children: A multi-site diagnostic accuracy study

Abstract

Aim: The American Academy of Pediatrics and the European Centre for Pediatric and Adolescent Medicine guideline define fever as a temperature >38.0°C for all ages and recommend use of rectal thermometers in children <3 years. Based on new literature, this definition of fever using a fixed threshold of 38.0°C needs to be re-examined. Design: A multi-site diagnostic accuracy study was conducted to compare an “age-based” threshold model with a “fixed” threshold over 38.0°C on a total of 894 patients of which 373 were ill. Methods: The “age-based” and “fixed” threshold fever determinations were then compared to a clinical categorization (“well” or “ill”) conducted by a clinician through a comprehensive examination. Results: The sensitivity and accuracy for the age-based thresholds were found to be superior to the fixed thresholds in all ages and current ear thermometers were found equivalent to rectal thermometers in infants <6 months.