Normative surface skin temperature changes due to blood redistribution: A prospective study.

The continuing development and manufacture of infrared devices, together with improvements in thermal body mapping techniques have simplified surface skin thermography which is being used more extensively than ever before. Normative thermography data, however, remains incomplete. A normative blood redistribution range of skin temperatures was established for use as a reference for laboratory infrared thermography (IT), thermal body mapping, and mass fever screenings. 500 healthy volunteers participated in this prospective study. To determine the maximum range of the skin temperature changes due to the posture-related physiological blood redistribution, the volunteers were asked to keep one extremity up and another extremity down whilst lying, sitting, and standing. We obtained 6000 hand and 400 foot temperature readings. The normal temperature was 29.1 ± 0.6 °C for the middle fingers and 27.8 ± 0.7 °C for the toes. The physiological temperature change during body position changes ranged from 4 to 6 °C (fingers: 27-31 °C; toes: 26-32 °C). At normal room temperature, the surface skin temperature may vary within this range due to blood redistribution. These changes reflect the individual variability of vasomotor activity. This physiological range of temperatures should be taken into account during IT and other thermography-involved investigations.