Validation of an objective scar pigmentation measurement by using a spectrocolorimeter

Scar pigmentation changes throughout its maturation process and it is often used as one of the indicators for scar maturation, yet it is often rated subjectively. The purpose of this study was to investigate the application of a commercial spectrocolorimeter to produce a reliable measurement on scar pigmentation. Commission Internationale de l'Eclairage (CIE) model of color has been adopted in this study for measurement of scar pigmentation 24 patients with hypertrophic scars at different stages of maturation were selected for the study, were inspected by two therapists using the Vancouver scar scale (VSS) and then using spectrocolorimeter for inter-rater reliability. The measurements were taken after 30min by the same group of therapists (test-retest reliability). Results indicated that the inter-rater reliability among the three therapists was satisfactory, with intra-class correlation coefficient (ICC) (2, 2) from 0.50 to 0.99 in all the three color parameters. The test-retest reliability of the spectrocolorimeter was satisfactory with ICC (3, 6) ranged from 0.95 to 0.99. A significant difference was also noted between the measurements of normal skin and hypertrophic scar (P<0.00, t-values: from 2.78 to 0.05, d.f.: from 29.7 to 46.00) in all color parameters, except the chroma C(*). We also found a positive relationship between VSS scores and the spectrocolorimeter readings. The spectrocolorimeter is found to be a reliable instrument to quantify scar pigmentation and to differentiate normal skin and scar tissue. With further studies, the constructs of scar properties could further be explored using this spectrocolorimeter.