In vivo transepidermal water loss: Validation of a new multi‐sensor open chamber water evaporation system Tewameter TM Hex

BACKGROUND: Instrumentation technology for transepidermal water loss measurements has not been substantially modified since its introduction by Nilsson in 1977. Recent progress in sensor development allowed a new sensor arrangement using a matrix of 30 sensors. Raw measurement values are processed with spatial statistical analysis. We aimed to compare the new, multi‐sensor probe (Tewameter TM Hex) with the established Tewameter TM 300 probe and to gain reference data for the new parameters of transepidermal energy loss and water vapor concentration on skin. MATERIAL AND METHODS: Baseline measurements and repeated measurements on the volar forearm and assessment on eight different anatomical locations were performed on 24 healthy volunteers (both gender) with the TM Hex and the TM 300. RESULTS: A significant correlation (p < 0.001; R‐coefficient = 0.9) between TM Hex and the TM 300 with a low coefficient of variance (CV) 11% for TM Hex and 19% for TM 300, could be assessed. The CV ranged between 7% (right inner upper arm) and 14% (palms). Average transepidermal heat loss ranged from 12 W/m(2) on the lower leg to 38.8 W/m(2) on the palm. CONCLUSION: The correlation between TM Hex and TM 300 along with the robustness of the measurements with the TM Hex shows that the new probe for assessment of epidermal barrier function is comparable to the TM 300. In most conditions, TM Hex provides more accurate measurements than TM 300. New parameters open the field to studying skin's water and energy balance.