The human vasoconstrictor assay, which is frequently used for potency comparisons of topically applied corticosteroids, relies on the visual measurement of skin blanching produced at the application site. In this report, three different methods of visual measurement were compared. A technique involving paired comparisons of vasoconstriction at adjacent sites was found to improve the assessment of relative vasoconstrictor activity. Corticosteroid creams containing 0.05% fluocinonide, 0.1% betamethasone valerate, and 1% hydrocortisone were evaluated in this study.
Poulsen BJ, Burdick K, Bessler S. Paired Comparison Vasoconstrictor AssaysA Comparison of Methods for the Determination of Relative Vasoconstrictor Potency of Topically Applied Corticosteroids. Arch Dermatol. 1974;109(3):367-371. doi:10.1001/archderm.1974.01630030027005