This was a cross-sectional study conducted in the pediatric department of a tertiary healthcare facility after approval from institute research and ethics committee. Written informed consent was obtained from the parents/legal representative. Infants from 1st day of life to 12 mo of age attending the pediatric outpatient department between 1st September to 31st October, 2018 were included in the study population. Sick and unstable infants were excluded. Axillary temperature was measured using mercury-in-glass thermometer (Enbee; Wuxi Moxibei Clinical Thermometer Co. Ltd.) after the axilla was wiped with a dry towel. The thermometer probe tip was placed under the axilla so that the tip was touching the skin and the temperature was measured after 5 min. Forehead temperature was recorded for NCIT with infrared thermometer Equinox EQ-IF-02 (Equinox Meditech Private Limited, New Delhi). Accuracy Range-10°C to 40°C) at approximately 0.5-1 cm distance from the glabella [5]. Measurements were taken by a trained nurse and the duty doctor from both the devices within 6 minutes.

The degree of agreement between the two methods was studied using the Bland and Altman method and the mean difference with 95% confidence limits noted for clinical consideration. SPSS 18.0 software was used to analyze the results.

Fig. 1 Bland altman plot showing the comparison of now-contact infrared thermometer (NCIT) and mercury thermometer readings.

Among 250 infants approached for the study, 7 (2.8%) were aged less than 28 days and 243 (97.2%) were aged from one month to one year. The mean (SD) infrared thermometer and temperature recordings of mercury-in-glass thermometer were 37.6 (0.91)°C and 37.6 (2.49) °C, respectively; mean difference -0.016 (95% CI: -0.32, 0.29). There was a significant correlation between NCIT and axillary thermometry measurements (r=0.22; P<0.001). Number of observed agreement was for 80.8% of observations, indicating moderate agreement (kappa=0.602) between both instruments (Fig. 1).

The mean (SD) temperature recordings of infrared thermometer and mercury-in-glass thermometer were 37.6 (0.91)°C and 37.6 (2.49)°C, respectively; mean difference. The present study established a good correlation between NCIT and axillary thermometry. Few earlier studies revealed conflicting results about the validity and accuracy of NCIT [4,6]. However, other studies have proven the clinical accuracy of NCIT compared to digital axillary thermometry [7-9]. The accuracy and reproducibility of NCIT in different body sites in comparison to conventional thermometers was demonstrated by Osio, et al. [8]. Digital thermometer is safer but its clinical accuracy is considered inferior to mercury-in-glass thermometer. Thus, we compared the clinical accuracy of NCIT with that of mercury-in-glass thermometer as also conducted by Chiappini, et al. [10] who reported significant correlation between the two methods (P<0·0001), similar to our study.

In our study, moderate agreement between NCIT and mercury thermometry reading was demonstrated. The cost effectiveness of NCIT in resource poor settings needs to be determined. Further studies comparing NCIT with rectal thermometry which is the gold standard would support the use of NCIT in clinical settings.

Contributors: ST,RB: collected data and managed the patients; ST reviewed the literature and drafted the initial version of the manuscript; SP: contributed to literature review and critically revised the manuscript. All authors approved the final version of the manuscript.

Funding: None; Competing interest: None stated.

1. Sollai S, Dani C, Berti E, Fancelli C, Galli L, Martino M, et al. Performance of a non-contact infrared thermometer in healthy newborns. BMJ Open. 2016:6;1-5.

2. El-Radhi AS. Determining fever in children: The search for an ideal thermometer. Br J Nurs. 2014; 23:91-4.

3. Smith J. Are electronic thermometry techniques suitable alternatives to traditional mercury in glass thermometry techniques in the pediatric setting? J Adv Nurs. 1998; 28: 1030-9.

4. Atas Berksoy E, Bag Ö, Yazici S, Çelik T. Use of noncontact infrared thermography to measure temperature in children in a triage room. Medicine (Baltimore). 2018; 97: 9737.

5. Robertson-Smith J, McCaffrey FT, Sayers R, Williams S, Taylor BJ. A comparison of mid-forehead and axillary temperatures in newborn intensive care. J Perinatol. 2015; 35:120-2.

6. Sethi A,　Patel D,　Nimbalkar A,　Phatak A,　Nimbalkar S. Comparison of forehead infrared thermometry with axillary digital thermometry in neonates. Indian Pediatr.　2013; 50:1153-4.

7. Wang K, Gill P, Wolstenholme J, Price CP, Heneghan C, Thomson M, et al. Non-contact infrared thermometers for measuring temperature in children: Primary care diagnostic technology update. Br J Gen Pract. 2014; 64: 681-3.

8. Osio CE, Carnelli V. Comparative study of body temperature measured with a non-contact infrared thermometer versus conventional devices. The first Italian study on 90 pediatric patients. Minerva Pediatr. 2007;59: 327-36.

9. Uslu S, Ozdemir H, Bulbul A, Comert S, Bolat F, Can E, et al. A comparison of different methods of temperature measurements in sick newborns. J Trop Pediatr. 2011; 57: 418-23.