Gel techniques in blood group serology

Serological investigation involves the interpretation of haemagglutination reactions, conventionally obtained in liquid phase systems. Gel centrifugation techniques utilise buffered dextran gels which separate red cells from their suspension media during a centrifugation phase, negative reactions resulting in the formation of a pellet of cells whereas agglutinations are trapped on top of, or throughout, the gel. The gels may be neutral or impregnated with specific reagents such as antihuman globulin, or antisera for phenotyping red cells. Gel systems have been found to be more sensitive than conventional serological techniques, particularly for the detection and identification of clinically significant antibodies. The elimination of the wash phase in the antiglobulin test, and the stability of the completed tests, provide greater reliability of results and enhance standardisation and control of laboratory procedures.