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Agglutination of red blood cells.



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.


References in periodicals archive ?
The results of Haemagglutination Antibody (HA) assay revealed a significant increase in antibody production among all the three treated groups in comparison to control group at 29th day of treatment.
After precisely 30 minutes, the end point of the titre was determined as the pair of wells where haemagglutination was clearly observed.
Considering these disadvantages, the WHO scientific group on Treponemal Infections recommended the use of Venereal Diseases Reference Laboratory (VDRL) or rapid plasma reagin (RPR) test and the Treponema pallidum haemagglutination assay (TPHA) for screening for syphilis7,19.
The rest of the routine laboratory tests including renal function tests, liver function tests, random blood sugar (RBS), Treponemal pallidum haemagglutination assay (TPHA), serum cryptococcal antigen (CRAG) titres, hepatitis B surface antigen (HBsAg) and brucella agglutination assay were unremarkable.
El diagnostico de sifilis se realizo inicialmente con una prueba presuntiva en suero (rapid plasma reagin [RPR SYPHILIS -Human]) con titulos entre 2 y 64 diluciones, y se confirmo aplicando la prueba (Treponema pallidum haemagglutination assay [TPHA syphilis Human]).
Unique Physico-chemical properties of Japanese B encephalitis antibody virus haemagglutination.
of India, Kolkata), Treponema pallidum haemagglutination assay (Plasmatec TPHA test kit, Hansard Diagnostics, United Kingdom) in VDRL reactive cases and fluorescent treponemal antibody absorption (FTA-ABS) test using FTA-Abs IgG and IgM IFA (Viro-Immun Labor-Diagnostika Gmbh, Oberursel & Virgo, Calbiotec, USA) in sera giving discrepant results in the above two tests were carried out.
40 Anti-HIV-1/-2 -- Electroencephalogram -- Abbreviations: ANCA = anti-neutrophil cytoplasmic antibody; FBS = fasting blood sugar; HIV = human immunodeficiency virus; RBC = red blood cell; RF = rheumatoid factor; TPHA = treponema pallidum haemagglutination assays; VDRL = Venereal Disease Research Laboratory; WBC = white blood cell.
The blood was tested for syphilis by Treponema Pallidum Haemagglutination.
The indirect haemagglutination assay (IHA) for hydatid disease was negative.
Seroconversion was defined as a fourfold increase in haemagglutination inhibition titre to at least 1:40.