Non-contact infrared thermometers compared with current approaches in primary care for children aged 5 years and under: a method comparison study

BACKGROUND: Current options for temperature measurement in children presenting to primary care include either electronic axillary or infrared tympanic thermometers. Non-contact infrared thermometers could reduce both the distress of the child and the risk of cross-infection. OBJECTIVES: The objective of this study was to compare the use of non-contact thermometers with the use of electronic axillary and infrared tympanic thermometers in children presenting to primary care. DESIGN: Method comparison study with a nested qualitative study. SETTING: Primary care in Oxfordshire. PARTICIPANTS: Children aged ≤ 5 years attending with an acute illness. INTERVENTIONS: Two types of non-contact infrared thermometers [i.e. Thermofocus (Tecnimed, Varese, Italy) and Firhealth (Firhealth, Shenzhen, China)] were compared with an electronic axillary thermometer and an infrared tympanic thermometer. MAIN OUTCOME MEASURES: The primary outcome was agreement between the Thermofocus non-contact infrared thermometer and the axillary thermometer. Secondary outcomes included agreement between all other sets of thermometers, diagnostic accuracy for detecting fever, parental and child ratings of acceptability and discomfort, and themes arising from our qualitative interviews with parents. RESULTS: A total of 401 children (203 boys) were recruited, with a median age of 1.6 years (interquartile range 0.79-3.38 years). The readings of the Thermofocus non-contact infrared thermometer differed from those of the axillary thermometer by -0.14 °C (95% confidence interval -0.21 to -0.06 °C) on average with the lower limit of agreement being -1.57 °C (95% confidence interval -1.69 to -1.44 °C) and the upper limit being 1.29 °C (95% confidence interval 1.16 to 1.42 °C). The readings of the Firhealth non-contact infrared thermometer differed from those of the axillary thermometer by -0.16 °C (95% confidence interval -0.23 to -0.09 °C) on average, with the lower limit of agreement being -1.54 °C (95% confidence interval -1.66 to -1.41 °C) and the upper limit being 1.22 °C (95% confidence interval 1.10 to 1.34 °C). The difference between the first and second readings of the Thermofocus was -0.04 °C (95% confidence interval -0.07 to -0.01 °C); the lower limit was -0.56 °C (95% confidence interval -0.60 to -0.51 °C) and the upper limit was 0.47 °C (95% confidence interval 0.43 to 0.52 °C). The difference between the first and second readings of the Firhealth thermometer was 0.01 °C (95% confidence i