MeSH definition : An evanescent cutaneous reaction occurring when antibody is injected into a local
area on the skin and antigen is subsequently injected intravenously along with a dye.
The dye makes the rapidly occurring capillary dilatation and increased vascular permeability
readily visible by leakage into the reaction site. PCA is a sensitive reaction for
detecting very small quantities of antibodies and is also a method for studying the
mechanisms of immediate hypersensitivity.;
An evanescent cutaneous reaction occurring when antibody is injected into a local
area on the skin and antigen is subsequently injected intravenously along with a dye.
The dye makes the rapidly occurring capillary dilatation and increased vascular permeability
readily visible by leakage into the reaction site. PCA is a sensitive reaction for
detecting very small quantities of antibodies and is also a method for studying the
mechanisms of immediate hypersensitivity.