photopatch test

noun
pho·​to·​patch test | \ ˈfōt-ō-ˌpach- How to pronounce photopatch test (audio) \

Medical Definition of photopatch test

: a test of the capability of a particular substance to photosensitize a particular human skin in which the substance is applied to the skin under a patch and the area is irradiated with ultraviolet light