Accuracy and acceptability of non-contact infrared compared to axillary and tympanic thermometers in children under 6 attending primary care: a method comparison study and nested qualitative evaluation

Background: Guidelines recommend the measurement of temperature in children presenting with fever symptoms using electronic axillary, or tympanic thermometers. Non-contact thermometry offers advantages yet have not been tested against the recommended methods in primary care. Aim: To compare two different non-contact infrared thermometers (NCITs) to axillary and tympanic thermometers in children aged 5 or under attending their GP with an acute illness. Design and setting: Prospective design in primary care. Method: Methods comparison study with nested qualitative component. Results: 401 children were recruited (median age 1.6 years, 50.62% boys). The mean difference between the Thermofocus NCIT and axillary thermometer was -0.14°C (95% CI -0.21 to -0.06); the lower limit of agreement was -1.57°C (95% CI -1.69 to -1.44) and the upper limit 1.29°C (95% CI 1.16 to 1.42). A second NCIT (Firhealth) had similar levels of agreement. However, the limits of agreement between tympanic and axillary thermometers were also wide. Parents expressed a preference for the practicality and comfort afforded by NCITs, and were predominantly negative about their child’s experience of axillary thermometers. However, there was a willingness to adopt whichever device was medically recommended. Conclusions In a primary care paediatric population, temperature measurements with NCITs varied by over a degree Celsius compared to axillary and tympanic approaches. However, there was also poor agreement between tympanic and axillary thermometers. Since clinical guidelines often rely on specific fever thresholds, clinicians should interpret peripheral thermometer readings with caution, and in the context of an holistic assessment of the child.