counterelectrophoresis

a laboratory technique in which an electric current is used to accelerate the migration of antibody and antigen through a buffered diffusion medium. Antigens in a gel medium in which the pH is controlled are strongly negatively charged and will migrate rapidly across the electric field toward the anode. The antibody in such a medium is less negatively charged and will migrate in an opposite or “counter” direction toward the cathode. If the antigen and antibody are specific for each other, they combine and form a distinct precipitin line.

The technique of CIE was first applied clinically in 1970 to detect hepatitis B antigen. With modification and refinement it is becoming increasingly useful as a means of detecting antigens or antibodies specific for a variety of infectious diseases. It can be especially valuable as an aid to accurate diagnosis of clinical bacterial infections and the selection of specific therapeutic agents for control of infections once the causative organisms are identified.