Temperature Recording Sites in Infants, Children, and Adults

Background: Axilla, mouth, and rectum are the most common sites for thermometric measurement. There is no universally accepted belief about how to predict one of them from others. Methods: In a cross-sectional hospital-based study at two educational hospitals in Qazvin Province, mercury in glass thermometers were used and then calibrated with digital thermometer within ±0.1 0C. The axillary temperature was compared with oral or rectal ones in 50 infants, 100 children, and 100 adults. Results: The mean difference between axillary and rectal temperature in infants was 0.366 0C (± 0.21), while those between oral and axilary in children and adults were 0.667 0C (±0.37) and 0.4940C (±0.3), respectively. Among infants, 98% of the oral and rectal readings were stabilized at 5 and 3 minutes, respectively. In children, 98% of the oral readings were stabilized at five but for axilla, 99% by 6 minutes. For adults, 95% of the oral readings were stabilized at 5 minutes while for axilla, it was 96% by 6 minutes. Conclusion: In less than 3 month old infants, axillary temperature accurately reflects the rectal temperature. Axillary and rectal thermometry in infants should be read after 5 and 3 minutes, while oral temperature in children and adults should be read after 6 and 5 minutes, respectively.