[Measurement of body temperature in daily practice]

Accurate measurement of body temperature is essential in routine medical practice. Development of new measurement methods, and awareness of mercury hazards are leading to the modification of our current practices. The range of body temperature in healthy individuals is 36.8 +/- 0.4 degrees C, but it may be influenced by many factors. Therefore, body temperature should be measured in a standardized fashion, preferably at rest, in the morning on waking. Febrile state is generally defined as a morning rectal temperature above 37.5 degrees C. Body temperature is largely dependent of the site of measurement. Rectal temperature is the highest, and oral temperature measured in the sublingual pocket close to the lingual artery generally the lowest. Tympanic membrane temperature is assumed to best reflect the core temperature. Axillary and cutaneous measures are unreliable. Mercury-in-glass thermometer used to measure rectal temperature still remains the reference in France. However, rectal measurement is inconvenient and associated with a risk of rectal injury and cross-infection. Moreover, mercury-in-glass thermometer results in high mercury pollution. Tendency is to replace it by either electronic thermometer to measure oral temperature, or infrared thermometer for tympanic membrane measure. Although reliable, chemical measures are still underused.