When it comes to measuring the transepidermal water loss (TEWL) of skin, there are two different measurement methods—open chamber and closed chamber. The C+K Tewameter® TM Hex is an example of a device using the open chamber and the Delfin VapoMeter is an example of a device that employs the closed chamber method for measuring TEWL.
While there has been some debate about which is the better aNd more accurate method of measuring TEWL, there are certain significant advantages that the open chamber method offers over the other. The following is an explanation of each differentiating factor.
The open chamber measurement method enables the probe to have multiple sensors, whereas the closed chamber method restricts the number of sensors that can be positioned inside the probe head to just one. For example, the Tewameter® TM Hex has 30 pairs of temperature and relative humidity sensors positioned on the inner walls of the hollow chamber. With more sensors, open chamber TEWL devices have a high volume of data flowing in that not only ensures maximum accuracy, but also quick and reliable stability of the TEWL reading. Moreover, even high water loss can be detected with the Tewameter® TM Hex as no water is collected inside the probe.
Open chamber probes allow for continuous measurement of TEWL, providing real-time data on changes in the skin barrier function over time. This means that the measurement can be reproduced, instead of extrapolating based on assumptions after a few seconds. The 30 pairs of sensors in the Tewameter® TM Hex ensure high accuracy levels of the continuous data stream.
While it is commonly believed that open chamber probes take quite some time to achieve stable results, this is not entirely true with all devices. The Tewameter TM Hex, because of its number of sensors, achieves a stable TEWL measurement within 20 seconds. Because of the high volume of data, a single measurement of a skin area is sufficient. For special applications and research, measurements over longer time periods can also be performed. Successive measurements can be performed immediately without any waiting time. With closed chamber probes, the chamber gets saturated after a couple of seconds and the measurement time is limited to 10 seconds. Hence, the general recommendation is to perform 3 measurements and average them to get the final result.
The Tewameter® TM Hex is calibrated to g/h/m² based on a sophisticated and fully traceable process. The user can periodically confirm the accuracy of the sensors by performing a calibration check and a zero adjustment, if needed.
Several research has been conducted on skin barrier function using open and closed chamber probes. There are research publications that claim that the open chamber method is more sensitive than the closed chamber technique. Here is an inexhaustive list of studies that mention the Tewameter®:
Agaram Industries is the exclusive Indian distributor of Courage+Khazaka. If you are convinced about the open chamber method of measuring TEWL and would like a quotation with the Tewameter® TM Hex, you can fill up this form or directly send an email to sales@agaramindia.com.
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