Indirect Hemagglutination Reaction

The indirect (passive) hemagglutination test (IDHA) is a laboratory method that is used to detect and determine antibodies in blood serum. This method is based on the interaction of an antigen (such as bacteria, viruses or toxins) with antibodies that are already present in a person's blood.

To carry out RNGA, special test systems consisting of antigen and antibodies are used. The antigen is placed in a well on the RNGA plate, and the antibodies are added to a test tube with blood serum. If antibodies are present in the serum, they bind to the antigen, forming an antigen-antibody complex. This complex is then added to the antigen plate.

In the presence of antibodies in the serum, the antigen-antibody complex forms agglutination - gluing of red blood cells, which leads to the formation of a visible sediment on the plate. The result of RNGA is assessed visually and can be positive or negative.