Errors in body temperature assessment related to individual variation, measuring technique and equipment

Abstract

Errors in body temperature measurement might seriously influence the evaluation of an individual's health condition. We studied individual variation, measurement technique and the equipment used when assessing body temperature. In the first part of the study, three volunteers performed repeated measurements for five mornings. In the second part, the morning rectal, oral, ear and axillary temperatures were measured once in 84 men and women (19-59 years). The repeated measurements showed a daily temperature difference of 0.1-0.4 degrees C in rectal and oral temperatures, 0.2 degrees C-1.7 degrees C in the ear and 0.1-0.9 degrees C in the axillary temperatures. In the sample of 84 subjects, men and postmenopausal women had a lower mean body temperature compared to premenopausal women. The mean deviation between rectal temperature, and oral, ear and axillary temperatures, respectively, was > 0.5 degrees C, with a large individual variation. In conclusion, in order to improve the evaluation of body temperature, the assessment should be based on the individual variation, the same site of measurement and no adjustment of oral, ear or axillary temperatures to the rectal site.

Fever or not fever – that’s the question: A cohort study of simultaneously measured rectal and ear temperatures in febrile patients with suspected infection

“…These gradients also vary between individuals. [10] Hence, there is no evidence of a k-factor that converts and equates the temperatures measured at various sites. [10][11][12][13][14][15] Nevertheless, it is still the rule rather than the exception to adjust and compare different sites, often based on the as-sumption that the rectal site is the most reliable and accurate site for body temperature measurement.…”

“…[10] Hence, there is no evidence of a k-factor that converts and equates the temperatures measured at various sites. [10][11][12][13][14][15] Nevertheless, it is still the rule rather than the exception to adjust and compare different sites, often based on the as-sumption that the rectal site is the most reliable and accurate site for body temperature measurement. [16][17][18] This paper focuses on repeated simultaneously measured rectal and ear body temperature in febrile patients, in order to highlight and discuss the consequences of this practice.…”

“…The pulmonary artery temperature is usually defined as core temperature, [10,21] but in clinical practice the rectal site has been considered to estimate the true body temperature. Hence, oral and axillary sites have traditionally been adjusted to the rectal site by adding 0.3…”

“…[4][5][6][7][8] Systematic reviews [27,28] and clinical trials have provided strong evidence that body temperature, measured at the rectal, oral, axillary and ear sites varies considerably between as well as within individuals. [10,29] One study [10] reported a temperature difference of -0.7…”

Effects of three different water temperatures on dehydration in competitive swimmers

“…After an equilibration time of 15 min in a sitting posture, blood was drawn from the antecubital vein to determine haemoglobin (Hgb), hematocrit (Hct), sodium (Na + ), potassium (K + ), magnesium (Mg ++ ) concentrations. Immediately (approximately 60 s on pool deck) before (Pre) each trial, rectal and axillary temperatures (T re and T ax , respectively) [11] were measured with traditional mercury thermometers set by a medical doctor (rectal thermometer was inserted 3 cm past the external anal sphincter for 3 min; axillary thermometer was inserted in axillary fossa for 5 min [12]). Core temperature was not measured.…”