Antigens Lab Report

Antibody Detection (Antibody Screen)

Three tubes were labeled 1-3 and to each patient serum was added. Group O reagent screening red cells 1 was added to tube 1, reagent screening red blood cells 2 was added to tube 2, and reagent screening red cells 3 was added to tube 3. The patient serum is the source of the antibody and the Group O reagent screening red cells are the source of the antigen in this screen. The patient’s serum has an antibody to an antigen on the reagent screening cells, the presence and identification of which is being determined in this test. The tubes were centrifuged and tubes were viewed under the agglutination viewer. Centrifugation promotes lattice formation and allows for easier viewing of agglutination.

Low Ionic Strength Solution (LISS) (N-Hance®) to each tube as added to each tube. LISS influences the sensitization stage of agglutination by increasing rate of antibody binding to specific antigen receptors on red blood cells, extending the duration of the antigen-antibody complex, and reducing the effects of sodium and chlorine ions1.

Tubes were incubated at 37°C for 15-20 minutes to allow for adequate time for antigen-antibody complex to reach equilibrium.

Antihuman globulin (AHG) was added to each tube, then tubes were centrifuged and view for agglutination. Antihuman globulin enhances the visibility of agglutination of IgG antibody-antigen complexes. IgG is too small to bridge the space between red blood cells caused by their zeta potential. AHG binding to IgG makes the lattice formation of hemagglutination more visible. Check cells (IgG-coated red blood cells) were added to tubes appearing negative and centrifuged to ensure AHG was added. A common false negative is not adding AHG to panel tubes. The AHG in the tube reacts with the IgG on the red cells to cause