Hemagglutination

Hemagglutination ( gr.Häm ( αἷμα ) blood, lat agglutinare attach ) means a visible clumping ( agglutination) of red blood cells. We distinguish:

In both cases, it is by the binding of an antibody to cross-link two erythrocytes ( precipitation ) between the red blood cells. This precipitate precipitates visible.

Direct hemagglutination

The direct hemagglutination plays for example in the blood group incompatibility a role. A person with blood group A wear on their red blood cells for the molecule. Your body does not produce antibodies against this antigen. However, a second person with blood type B has in their blood antibodies against this blood group attribute A. If now the blood or serum of the person transferred to the blood group B the person with the blood group A, the antibodies bind to the corresponding antigens on the red cells and it comes to the formation of immune complexes in the blood vessels and thus to the transfusion incident. To avoid this, before a blood transfusion (among other studies ), a bedside test performed, in which the blood of the recipient is examined with reference to the corresponding antibodies and agglutination blood group is determined again immediately prior to transfusion.

Indirect hemagglutination

The indirect hemagglutination makes you look serology test to use. Firstly, certain pathogens can be detected indirectly when the erythrocytes are loaded with specific antigens (eg Vi antigen in typhoid, Latexhämagglutinationstest in syphilis ).

Hemagglutination inhibition

In the hemagglutination inhibition test hemagglutination inhibition between antigen-loaded erythrocytes and antiserum through a sample is measured. This includes many of the antigens to be examined, the hemagglutination precipitates weaker as the antibody bound to the reinforced free antigen of the sample and so that less contributes to crosslinking of the erythrocytes. The test is also used for quantification of antibody against hemagglutinating viruses (especially influenza viruses). If influenza viruses erythrocytes added, it comes to a complete hemagglutination. But containing the product to be examined serum antibodies against the influenza virus, a hemagglutination is inhibited. About dilution series, so-called titration, the amount of serum to be examined can be determined, which can just prevent hemagglutination by a predetermined amount of virus. This is referred to as Hämagglutinationshemmtiter.