Assessing the sensitivity of two TEWL measuring methods: open vs. closed chamber

Transepidermal water loss (TEWL) is a key parameter in the assessment of skin barrier impairment and recovery. The aim of this study was to perform a comparative assessment of the two types of TEWL instruments, with specific emphasis on their sensitivity in detecting small differences. An open chamber (Tewameter TM300, Courage & Khazaka, Germany) and a closed, condenser-chamber instrument (AquaFlux AF200, Biox Systems, UK) were used in the study. A complimentary skin hydration test (Corneometer CM825, Courage & Khazaka, Germany) was also carried out. In the first study, the closed chamber results have revealed two additional sets of significantly different data, in comparison to the open chamber method. In the second study, where the level of barrier impairment was higher, both methods have resulted in the same statistical outcome. It was concluded that the condenser-chamber instrument possesses higher sensitivity than the open chamber when assessing small differences in TEWL, under the same experimental conditions.