Hemagglutination (redirected from hemagglutination (HA) test)

hemagglutination [‚hē·mə‚glüd·ən′ā·shən]

(immunology)

Agglutination of red blood cells.

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Hemagglutination 

the agglutination and subsequent precipitation of red blood cells, caused by hemagglutinins, bacteria, viruses, and agents capable of being adsorbed onto the surface of red blood cells.

Clusters of red blood cells, distinguishable to the naked eye as heaps, lumps, and clumps, are formed during hemagglutination. Hemagglutination is caused by the interaction of the agglutinogens present in red blood cells with plasma that contains agglutinins. Each agglutinogen has a corresponding agglutinin. The term “isohemagglutination” is used to designate the hemagglutination that takes place during the interaction of different blood groups in animals of the same species; “heterohemagglutination” is the term applied to the process in animals of different species. The laws of blood transfusion and identification of blood groups are based on the hemagglutination reaction. After the transfusion of incompatible blood, hemagglutination may occur in the bloodstream and cause severe (sometimes fatal) complications. In forensic medicine the hemagglutination reaction is used to determine the source of blood stains and as an additional test in cases of disputed paternity. In microbiology and immunology, the hemagglutination reaction is used to determine antiserum activity, for example, or type of virus. A distinction is made between active hemagglutination, which is caused by the direct action of an appropriate agent on the red blood cells, and passive hemagglutination, caused by a specific antiserum to the antigen previously adsorbed by the red blood cells. Hemagglutination may be caused by antibodies acting against one’s own red blood cells (auto-hemagglutination) or against red blood cells of the same species (homoagglutination) as well as by the polysaccharides of the causative bacteria of tuberculosis, plague, and tularemia, by the polysaccharides of the colon bacillus, and by the viruses of influenza, mumps, pneumonia of white mice, swine and horse influenza, smallpox vaccine, yellow fever, and other diseases.

KH. KH. PLANEL’ES and A. M. POLIANSKAIA