Diagnostic immunology

Diagnostic immunology is a collective term for a variety of diagnostic techniques that rely on the specificity of the bond between antibodies and antigenes. Diagnostic immunology is well-suited for the detection of even the smallest of amounts of (bio)chemical substances. Antibodies specific for a desired antigen can be conjugated with a radiolabel, fluorescent label, or color-forming enzyme and are used as a "probe" to detect it.

Well known applications of this include immunoblotting, ELISA and immunohistochemical staining of microscope slides. The speed, accuracy and simplicity of such tests has led to the development of rapid techniques for the diagnosis of disease, microbes and even illegal drugs in vivo (of course tests conducted in a closed environment have a higher degree of accuracy). Such testing is also used to distinguish compatible blood types.