<unk>  is a test for blanchability performed by applying pressure with a finger or glass slide and observing color changes. It is used to determine whether a lesion is vascular (inflammatory or congenital), nonvascular (nevus), or hemorrhagic (petechia or purpura). Hemorrhagic lesions and nonvascular lesions do not blanch ("negative<unk> "); inflammatory lesions do ("positive<unk> ").<unk>  is sometimes used to identify sarcoid skin lesions, which, when tested, turn an apple jelly color.
Diascopy
Scanning laser polarimetry
Gelotology
Alcian blue stain
Endomicroscopy
Urinometer
Diffuse optical imaging
Sabin–Feldman dye test