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agglutination of erythrocytes.
hemagglutination inhibition (HI, HAI) test
1. a highly sensitive procedure for the measurement of soluble antigens in biologic specimens; the amount of hemagglutination reflects the amount of free antibody present after reaction with the specimen and thus varies inversely with amount of antigen in the specimen.
2. a procedure for the measurement of serum antibodies directed against a hemagglutinating virus; the highest dilution of serum that completely inhibits hemagglutination by a standardized viral preparation is reported as the hemagglutination titer.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


The agglutination of red blood cells; may be immune as a result of specific antibody either for red blood cell antigens themselves or other antigens that coat the red blood cells, or may be nonimmune as in hemagglutination caused by viruses or other microbes.
Synonym(s): hemoagglutination
Farlex Partner Medical Dictionary © Farlex 2012


The agglutination of red blood cells; may be immune (as a result of specific antibody to red blood cell antigens or other antigens that coat the red blood cells), or nonimmune (as in hemagglutination caused by viruses or other microbes).
Synonym(s): haemagglutination.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


The clumping or clustering of red blood cells caused by certain viruses, antibodies, or other substances.
Mentioned in: Rubella Test
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
HI, hemagglutination inhibition assay; +, positive; - negative; [+ or -], equivocal.
We, the authors of the article entitled "Detection of infection by Toxoplasma gondii through indirect hemagglutination and PCR in feral wild boar (Sus scrofa)", declare, for the intended purposes; that although, the project with the original data was not submitted for evaluation of the Ethics Committee of the Universidade Federal do Mato Grosso, we are aware of the content of the guidelines of the National Council for Control of Animal Experimentation--CONCEA <http://www.mct.gov.br/index.php/ content/view/310553.html> for studies with animals.
The blood samples were randomly collected in winter and summer from 1650 birds to detect avian influenza by Hemagglutination Inhibition (HI) test through the titration of AI virus type H5 (OIE, 2009).
Confirmation testing that the laboratories recommended and/or performed reflexively after a positive initial screen (question 5) includes 34.7% (615 of 1774) that use the fluorescent treponemal antibody-absorption test, 23.1% (410 of 1774) that use an agglutination or hemagglutination assay, and 23.2% (412 of 1774) that use an RPR assay.
In addition, various serological tests such as ELISA, immunoelectrophoresis, indirect hemagglutination, and latex agglutination tests can be used to evaluate the diagnosis, followup, and posttreatment relapse of the disease [20].
In this study, we screened the extracts of approximately 40 Chinese medicinal herbs, among which we found Rhodiolae Kirliowii Radix et Rhizoma and Crataegus Pinnatifidae Fructus extracts to effectively inhibit the hemagglutination activity of BKPyV and JCPyV virus-like particles (VLPs).
The result of the Treponema pallidum hemagglutination assay (TPHA) was reactive.
Different coupling agents were used to bind measles antigen with erythrocyte suspensions of different concentrations collected from different species for standardization of Indirect Hemagglutination Assay (IHA) which was then used for testing of serum samples for the detection and quantification anti-measles antibodies.
ETR1, ETR2 and ETR3 hemagglutinated human, sheep and rat erythrocytes and this hemagglutination was specifically inhibited by galactose and its derivatives.
Investigations performed in all cases were complete blood count, serum biochemistry, urinanalysis, the Casonis (skin intradermal test) and Weinberg (complement fixation test) tests, Indirect Hemagglutination Test and Immuno-electrophoresis.
Hemagglutination titration assays were then performed weekly to measure changes in circulating antibody titer.

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