The AquaFlux out-performs all its competitors in terms of accuracy, sensitivity, repeatability, reproducibility and versatility. Below, we present data on three aspects, namely (A) how do they correlate, (B) how do the numbers compare and (C) where's the difference.

(A) How do they correlate?
AquaFlux measurements correlate well with open-chamber measurements. This has been established in a number of studies on different skin sites and many volunteers. The example shown below is from a study performed by independent scientists experienced in the use of open-chamber TEWL instruments.

(B) How do the numbers compare?
Although the measurements correlate well, the the numbers generally differ. This is due to calibration differences, with no agreement among manufacturers about best practice. The calibration disagreement in the above case is large, approximately a factor of 2.

Such disagreements can be resolved by the traceable droplet calibration method developed in collaboration with the UK National Physical Laboratory.

(C) Where's the difference?
The main difference between AquaFlux and open-chamber methods is in the quality of the measurements. This is illustrated below, where an AquaFlux signal is compared with those from two open-chamber instruments under well-controlled laboratory conditions using procedures recommended by the manufacturer, but without a shielding box. Ambient air movements do not affect closed chamber AquaFlux signals, but cause additional disturbance to open-chamber signals.

Signal fluctuations cause scatter in TEWL measurements. One comparative test, for example, found AquaFlux TEWL repeatability to be more than ten times better (CV=1.4%) than comparable Evaporimeter repeatability (CV=16%). See IFSCC Magazine, 5(4), 297-301, 2002 for details.

How this translates into practice is illustrated in the figure below, where two skin sites of the same volunteer were repeatedly tested in alternation.