Usefulness of infrared thermometer for measurement of body temperature in dogs

Aim: Accurate measurement of body temperature is important for diagnosis as well as investigating a patient. Various noninvasive thermometers are available for humans today, but there is no consensus on their usefulness in dogs. In this study, two non-contact infrared thermometers [IRT: VisioFocus PRO 06480 (VIRT)-Italy and Weewell WTN 570 (WIRT)-China] in body temperature measurement from the axillary (A) region and cornea (C) of dogs were compared with digital rectal thermometer [DRT: Kruuse Digital Thermometer, Katalog No.: 291126 (KDRT)-Denmark] considered as gold standart to evaluate their clinical use. Material and Methods: A total of 150 dogs of varying age and either sex who were admitted to our hospital were enrolled. Measurements of body temperature in every single dog were made from rectum with DRT and from axillary region and cornea with two IRT, respectively. Considering DRT readings as the reference value, temperature readings by both IRT at axillary region and cornea were compared with this reference value (differences). Correlations between the measurement methods was evaluated with Spearman test and their compatibility with Passing Bablok regression and Bland-Altman test. Results: The median body temperatures measured from the axillary region with VIRT and Weewell WIRT were 38.30 °C and 37.90 °C, respectively, and these values were significantly lower than the KDRT measurement (38.70 °C). Compared with median KDRT (38.70 °C) also corneal measurements of body temperature by both IRT (VIRT: (37.50 °C; WIRT: 37.00 °C) resulted in a significant lower result. Axillary and corneal measurements of body temperature by both IRT were poorly correlated with DRT. Passing Bablok regression indicated significant constant and/or propotional biases between two measurement methods. Bland-Altman analysis showed biases and wide limits of agreement not acceptable for clinical purposes. Conclusion: In this study, two non-contact infrared thermometers, whose performance was evaluated in the measurement of body temperature from the axillary region and cornea in dogs, offer easy and quick measurement, but they cannot be used clinically instead of digital rectal thermometers.