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

Area of Science:

• Pediatrics
• Diagnostic Accuracy
• Clinical Thermometry

Background:

• Current pediatric fever guidelines from the American Academy of Pediatrics and the European Centre for Pediatric and Adolescent Medicine define fever as a temperature >38.0°C for all ages.
• These guidelines recommend rectal thermometers for children under 3 years old.
• Emerging literature suggests the fixed 38.0°C fever threshold may require re-examination.

Purpose of the Study:

• To compare the diagnostic accuracy of an age-based fever threshold model against a fixed 38.0°C threshold.
• To evaluate the performance of current ear thermometers against rectal thermometers in infants.

Main Methods:

• A multi-site diagnostic accuracy study involved 894 patients, including 373 who were ill.
• Fever determinations using both age-based and fixed thresholds were compared.
• Clinical categorization of patients as "well" or "ill" was performed by a clinician via comprehensive examination.

Main Results:

• The age-based fever threshold model exhibited superior sensitivity and accuracy across all age groups compared to the fixed 38.0°C threshold.
• Current ear thermometers demonstrated performance equivalent to rectal thermometers in infants under 6 months of age.

Conclusions:

• An age-based fever threshold model offers improved accuracy for identifying illness in children compared to a universal fixed threshold.
• Ear thermometers are a reliable alternative to rectal thermometers for fever detection in young infants.