Direct fluorescent antibody

A direct fluorescent antibody (DFA or dFA), also known as 'direct immunofluorescence', is an antibody that has been tagged in a direct fluorescent antibody test. Its name derives from the fact that it directly tests the presence of an antigen with the tagged antibody, unlike western blotting, which uses an indirect method of detection, where the primary antibody binds the target antigen, with a secondary antibody directed against the primary, and a tag attached to the secondary antibody. A direct fluorescent antibody (DFA or dFA), also known as 'direct immunofluorescence', is an antibody that has been tagged in a direct fluorescent antibody test. Its name derives from the fact that it directly tests the presence of an antigen with the tagged antibody, unlike western blotting, which uses an indirect method of detection, where the primary antibody binds the target antigen, with a secondary antibody directed against the primary, and a tag attached to the secondary antibody. Commercial DFA testing kits are available, which contain fluorescently labelled antibodies, designed to specifically target unique antigens present in the bacteria or virus, but not present in mammals (Eukaryotes). This technique can be used to quickly determine if a subject has a specific viral or bacterial infection.