Serologic Techniques for blood grouping Dr. Ahmad Hassaneen

Anti-A , Anti-B and Anti-D reagents

Slide test for ABO grouping Note: “Serum” means the Reagent that contains the antibodies i.e. Anti-A and Anti-B Slide test for ABO grouping

Tube method

Microplate (96 wells) method Microplate (96 wells) method. Reagents added to the patients samples are written on left. Interpretation (blood groups of patients is written below. Red compact button =agglutination (+ve). Uniform suspension = no agglutination (- ve)

Column agglutination (Gel technology) -Microtubes filled with antisera and dextran acrylamide gel (which functions as a reaction medium and also as a filter). -After addition of red cells to the top of the tube , hemagglutinates (if formed) are trapped at the top of the tube (positive test). -Non-agglutinated red cells pass through the gel → forming a button at the bottom of tube (negative test). -Advantages: 1-Easy 2-Accurate and standardized 3-Requires a small sample volume 4-No need for washing of red cells 5-Reduces the exposure to biohazardous samples.

Column agglutination (Gel method)

Techniques in Rh D grouping: -Individuals with D antigen on their RBCs are called Rh-positive. -Individuals without D antigen on their RBCs are called Rh-negative. -If Rh-negative individuals are transfused with Rh-positive blood , they will produce anti-D antibodies → in these sensitized people , re-exposure to D antigen will lead to hemolytic transfusion reaction or , in pregnant women , hemolytic disease of newborn. -Rh typing is done by forward method . -Reverse method is not done because of absence of Anti-D in the majority of Rh-negative persons.