agglutination (a-glu-ti-na´shun)

1. The process by which suspended bacteria, cells, or other particles of similar size are caused to adhere and form into clumps; similar to precipitation, but the particles are larger and are in suspension rather than being in solution. For specific a. reactions in the various blood groups, see Blood Groups appendix. 2. Adhesion of the surfaces of a wound. [L. ad, to, + gluten, glue]
acid a. the clumping together of certain microorganisms at high hydrogen ion concentration.
bacteriogenic a. the clumping of erythrocytes as a result of effects of bacteria or their products.
cold a. a. of red blood cells by their own serum (see autoagglutination), or by any other serum when the blood is cooled below body temperature, but most pronounced below 25°C; the phenomenon results from cold agglutinins; may be seen occasionally in the blood of apparently normal persons or as a pathologic finding in patients with primary atypical pneumonia, infectious mononucleosis, and other viral diseases, certain protozoan infections, or lymphoproliferative neoplasms. See autoagglutination.
cross a. group a
false a. 1. pseudoagglutination (1) 2. rouleaux formation
group a. a. by antibodies specific for minor (group) antigens common to several microorganisms, each of which possesses its own major specific antigen.cross a;
immune a. a. caused by antibody (agglutinin) that is specific for the suspended microorganism, cell, or for an antigen that has been coated on a particle of suitable size.
indirect a. passive a
mixed a. mixed agglutination reaction
nonimmune a. 1. a. caused by a lectin having a degree of specificity, the mechanism of which is not understood; 2. a. that results from nonspecific factors, as in the case of acid a. or spontaneous a.
passive a. a. of particles that have been coated with soluble antigen, by antiserum specific for the adsorbed antigen.indirect a;
spontaneous a. nonspecific clumping of organisms in saline related to lack of polar groups in electrolyte solution.


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