The inter-rater and test-retest reliability of skin thickness and skin elasticity measurements by the DermaLab Combo in healthy participants.

Background: For several purposes, skin parameters like thickness and elasticity can be measured. However, little is known about the accuracy of those measurements.

Aim: The aim of this study was to determine the intrarater and test-retest reliability of skin thickness and elasticity measurements performed with the DermaLab Combo®.

Methods: A total of 49 participants were included in this study. Skin thickness and elasticity were measured at six defined locations on the dominant arm. Measurements were repeated two times by the same observer to determine the test-retest reliability. To determine the inter-rater reliability, a second observer repeated the measurements once.

Results: Inter-rater and test-retest reliability for elasticity measurements fluctuates per location and per parameter: Inter-rater intraclass correlation coefficient (ICC) ranged from 0.23 to 0.80, and test-retest ICC ranged from 0.25 to 0.84. Skin thickness was measured reliable by every observer on every location, with a test-retest ICC ranging from 0.71 to 0.83 and an inter-rater ICC ranging from 0.69 to 0.80.

Conclusion: The DermaLab Combo® showed a good inter-rater reliability when measuring skin thickness and elasticity. Not all locations are suitable for reliable inter-rater or test-retest measurements. The device is difficult to use by inexperienced users, as the echo probe is sensitive to small movements.