Evaluating the Interchangeability of Forehead, Tympanic, and Axillary Thermometers in Italian Paediatric Clinical Settings: Results of a Multicentre Observational Study

Clinical accuracy and agreement between tympanic and forehead body temperature measurements for screening of patients with COVID-19

AIM

To investigate the accuracy, reliability and agreement between infrared forehead thermometers versus infrared tympanic thermometers temperature, a cross-sectional study was conducted in April 2020.

METHODS

The forehead and tympanic temperatures of 615 subjects were measured simultaneously in three exposed SARS-COV-2 groups at one hospital in Iran, during April 2020. These comparisons were evaluated by Bland-Altman Plot, repeatability, Passing-Bablok regression and Lin's concordance correlation coefficient. The receiver operating characteristic (ROC) analysis was done to describe the discrimination accuracy of a diagnostic test. The study adhered to STROBE checklist for cross-sectional studies.

RESULTS

A Bland-Altman plot indicated that the limits of agreement between the forehead and tympanic temperature were -0.259 to +0.19°C. Passing-Bablok regression analysis illustrated that the infrared forehead was not linearly related to tympanic temperatures (reference method), with a slope estimate that was significantly different from 1.00. The infrared forehead thermometer showed poor precision and lower accuracy than the tympanic. The forehead temperature readings had 60.0% sensitivity and 44.4% specificity (p > .05) to predict disease.

CONCLUSION

According to the results of study, there is no evidence that the assessment of temperature by infrared forehead thermometer could discriminate between the two groups (positive and negative).

Clinical evaluation of non-contact infrared thermometers

Non-contact infrared thermometers (NCITs) are being widely used during the COVID-19 pandemic as a temperature-measurement tool for screening and isolating patients in healthcare settings, travelers at ports of entry, and the general public. To understand the accuracy of NCITs, a clinical study was conducted with 1113 adult subjects using six different commercially available NCIT models. A total of 60 NCITs were tested with 10 units for each model. The NCIT-measured temperature was compared with the oral temperature obtained using a reference oral thermometer. The mean difference between the reference thermometer and NCIT measurement (clinical bias) was different for each NCIT model. The clinical bias ranged from just under - 0.9 °C (under-reporting) to just over 0.2 °C (over-reporting). The individual differences ranged from - 3 to + 2 °C in extreme cases, with the majority of the differences between - 2 and + 1 °C. Depending upon the NCIT model, 48% to 88% of the individual temperature measurements were outside the labeled accuracy stated by the manufacturers. The sensitivity of the NCIT models for detecting subject's temperature above 38 °C ranged from 0 to 0.69. Overall, our results indicate that some NCIT devices may not be consistently accurate enough to determine if subject's temperature exceeds a specific threshold of 38 °C. Model-to-model variability and individual model accuracy in the displayed temperature were found to be outside of acceptable limits. Accuracy and credibility of the NCITs should be thoroughly evaluated before using them as an effective screening tool.

Evaluating the interchangeability of infrared and digital devices with the traditional mercury thermometer in hospitalized pediatric patients: an observational study

Gradual replacement of the mercury thermometers with alternative devices is ongoing around the world in a bid to protect human health and the environment from the adverse effects of mercury. However, to reduce the risks of misdiagnosis, unnecessary treatments, and omission of care in pediatric populations, more evidence on the reliability of alternative thermometers is needed. The aim of this comparative observational study was to detect any differences in temperature measurements between the use of the axillary mercury thermometer and the alternative techniques. Temperature values in degree Celsius (°C) were measured in a group of Albanian children aged up to 14 years using mercury and digital axillary thermometers, as well as forehead and tympanic infrared thermometers. The digital axillary device, compared with the mercury one, showed no clinically significant difference in the mean values (− 0.04 ± 0.29 °C) and the narrowest 95% level of agreement (+ 0.53 °C to − 0.62 °C) in the paired comparisons. For cut-off point of 37.5 °C, the digital axillary thermometer showed the highest levels of sensitivity (72.5%) and specificity (99.1%) in detecting fever. This study indicates that the digital axillary thermometer may be the better option since it adequately balances accuracy, safety, and children’s comfort.

Tunable diode laser-based two-line thermometry: a noncontact thermometer for active body temperature measurement

A precise and fast optical thermometer based on a tunable diode laser absorption spectroscopy is developed for breath diagnostics with relevance to noncontact body temperature measurement. As water vapor (H₂O) is the major component in human breath, two optimal absorption lines of H₂O at 1392 nm and 1371 nm are selected for sensitive body temperature measurement by systematically investigating the near-infrared spectral database. The optical thermometer is developed using two distributed feedback diode lasers with the time-division multiplexing technique to achieve real-time measurement. The sensor performance such as accuracy, repeatability, and time response is tested in a custom-designed gas cell with its temperature controlled in the range of 20°C-50°C. By measuring the test air with different water concentrations, the sensor consistently shows a quadratic response to temperature with an R-squared value of 0.9998. Under the readout rate of 1 s, the sensor achieves a measurement precision of 0.16°C, suggesting its potential applications to fast, accurate, and noncontact body temperature measurements.

Investigation of the Impact of Infrared Sensors on Core Body Temperature Monitoring by Comparing Measurement Sites

Many types of thermometers have been developed to measure body temperature. Infrared thermometers (IRT) are fast, convenient and ease to use. Two types of infrared thermometers are uses to measure body temperature: tympanic and forehead. With the spread of COVID-19 coronavirus, forehead temperature measurement is used widely to screen people for the illness. The performance of this type of device and the criteria for screening are worth studying. This study evaluated the performance of two types of tympanic infrared thermometers and an industrial infrared thermometer. The results showed that these infrared thermometers provide good precision. A fixed offset between tympanic and forehead temperature were found. The measurement values for wrist temperature show significant offsets with the tympanic temperature and cannot be used to screen fevers. The standard operating procedure (SOP) for the measurement of body temperature using an infrared thermometer was proposed. The suggestion threshold for the forehead temperature is 36 °C for screening of fever. The body temperature of a person who is possibly ill is then measured using a tympanic infrared thermometer for the purpose of a double check.