Research Article

Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs

Volume: 10 Number: 2 October 24, 2026

Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs

Abstract

Objectives: In canine veterinary medicine, determining body temperature is essential for clinical diagnosis, patient monitoring, and evaluating animal welfare. Although digital rectal and non-contact infrared (IR) thermometers are frequently used as alternatives to traditional mercury-in-glass thermometers, their clinical agreement remains controversial. This study aimed to evaluate the agreement of digital rectal and non-contact IR thermometers with mercury-in-glass rectal thermometry in dogs and to explore the relationships between measurement methods using regression analysis. Materials and Methods: A total of 151 client-owned dogs (63 males and 88 females), including both clinically healthy dogs and dogs with various health conditions, were included in this comparative study. The animals were not stratified according to their clinical health status. Body temperature was measured sequentially using a mercury-in-glass rectal thermometer (reference method; 3-minute measurement duration), a digital rectal thermometer, and a non-contact IR thermometer positioned 5 cm from the hairless inguinal region. Data were evaluated using linear mixed-effects models, Pearson's correlation, linear regression, and Bland–Altman agreement analysis. Results: Mean body temperatures were 38.71 ± 0.05 °C for mercury-in-glass, 38.58 ± 0.05 °C for digital rectal, and 37.94 ± 0.05 °C for IR thermometers (p < 0.0001). A strong positive correlation was observed between digital rectal and mercury-in-glass measurements (r = 0.84; p < 0.0001; 95% CI: 0.79–0.89), whereas a weak positive correlation was found between IR and mercury-in-glass measurements (r = 0.35; p < 0.0001; 95% CI: 0.20–0.48). Bland–Altman analysis showed a mean difference of 0.13 °C (95% limits of agreement: −0.51 to 0.77 °C) between mercury-in-glass and digital rectal thermometers, compared with 0.77 °C (95% limits of agreement: −0.88 to 2.42 °C) between mercury-in-glass and non-contact IR thermometers. Conclusions: Digital rectal thermometry demonstrated a stronger correlation with mercury-in-glass rectal thermometry than non-contact IR thermometry. However, clinical interchangeability should be interpreted cautiously and evaluated in relation to the observed limits of agreement. Non-contact IR measurements obtained from the inguinal region showed greater variability, suggesting that this method should not be considered a direct substitute for rectal temperature measurement under the conditions investigated.

Keywords

Supporting Institution

Afyon Kocatepe University Scientific Research Projects Coordination Unit (BAPK), Project No: 18.KARİYER.204.

Project Number

18.KARİYER.204

Ethical Statement

This study did not require animal ethics committee approval in accordance with Article 8-k of the Regulation on the Working Procedures and Principles of Animal Experiments Local Ethics Committees, as confirmed by the Afyon Kocatepe University Animal Experiments Local Ethics Committee (AKUHADYEK) (Decision No: 49533702/122).

Thanks

Not applicable

References

  1. Abioja MO, Akinjute OF, Iyanda OA, Williams TJ, James IJ, Daramola JO. Comparison of infrared, electronic digital, and mercury-in-glass thermometers: 1. West African dwarf goats. Bull Anim Health Prod Afr. 2017; 65(4):659-668.
  2. Bland JM, Altman DG. Comparing methods of measurement: Why plotting difference against standard method is misleading. Lancet. 1995; 346(8982):1085-1087.
  3. Casas-Alvarado A, Martínez-Burnes J, Mora-Medina P, et al. Thermal and circulatory changes in diverse body regions in dogs and cats evaluated by infrared thermography. Animals (Basel). 2022; 12(6):789.
  4. Cichocki B, Dugat DA, Payton M. Agreement of axillary and auricular temperature with rectal temperature in systemically healthy dogs undergoing surgery. J Am Anim Hosp Assoc. 2017; 53(5):291-296.
  5. Cugmas B, Šušterič P, Gorenjec NR, Plavec T. Comparison between rectal and body surface temperature in dogs by the calibrated infrared thermometer. Vet Anim Sci. 2020; 9:100120.
  6. Cynthia MK. Nervous system. In: Kahn CM, Line S, eds. The Merck Veterinary Manual. 10th ed. Whitehouse Station: Merck and Co., Inc.; 2010. pp.1105-1116.
  7. Goic JB, Reineke EL, Drobatz KJ. Comparison of rectal and axillary temperatures in dogs and cats. J Am Vet Med Assoc. 2014; 244(10):1170-1175.
  8. Gomart SB, Allerton FJW, Gommeren K. Accuracy of different temperature reading techniques and associated stress response in hospitalized dogs. J Vet Emerg Crit Care (San Antonio). 2014; 24(3):279-285.

Details

Primary Language

English

Subjects

Veterinary Internal Medicine

Journal Section

Research Article

Publication Date

October 24, 2026

Submission Date

September 24, 2026

Acceptance Date

October 14, 2026

Published in Issue

Year 2026 Volume: 10 Number: 2

APA
Başer, D. F., Acar, A., Uçar, M., Tunç, A. C., & Çıngı, C. Ç. (2026). Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs. Turkish Journal of Veterinary Research, 10(2). https://doi.org/10.47748/tjvr.2047385
AMA
1.Başer DF, Acar A, Uçar M, Tunç AC, Çıngı C Ç. Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs. TJVR. 2026;10(2). doi:10.47748/tjvr.2047385
Chicago
Başer, Durmuş Fatih, Abuzer Acar, Mehmet Uçar, Ahmet Cihat Tunç, and Cenger Çağrı Çıngı. 2026. “Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs”. Turkish Journal of Veterinary Research 10 (2). https://doi.org/10.47748/tjvr.2047385.
EndNote
Başer DF, Acar A, Uçar M, Tunç AC, Çıngı C Ç (October 1, 2026) Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs. Turkish Journal of Veterinary Research 10 2
IEEE
[1]D. F. Başer, A. Acar, M. Uçar, A. C. Tunç, and C. Ç. Çıngı, “Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs”, TJVR, vol. 10, no. 2, Oct. 2026, doi: 10.47748/tjvr.2047385.
ISNAD
Başer, Durmuş Fatih - Acar, Abuzer - Uçar, Mehmet - Tunç, Ahmet Cihat - Çıngı, Cenger Çağrı. “Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs”. Turkish Journal of Veterinary Research 10/2 (October 1, 2026). https://doi.org/10.47748/tjvr.2047385.
JAMA
1.Başer DF, Acar A, Uçar M, Tunç AC, Çıngı C Ç. Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs. TJVR. 2026;10. doi:10.47748/tjvr.2047385.
MLA
Başer, Durmuş Fatih, et al. “Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs”. Turkish Journal of Veterinary Research, vol. 10, no. 2, Oct. 2026, doi:10.47748/tjvr.2047385.
Vancouver
1.Durmuş Fatih Başer, Abuzer Acar, Mehmet Uçar, Ahmet Cihat Tunç, Cenger Çağrı Çıngı. Comparison of Mercury, Digital Rectal, and Non-Contact Infrared Thermometry for Body Temperature Measurement in Dogs. TJVR. 2026 Oct. 1;10(2). doi:10.47748/tjvr.2047385