Principle: | Procedure: | Limitations: | Quality Control: | References:
Red-cell-containing components selected for transfusion to a patient with a clinically significant antibody must be tested and found to be negative for the appropriate antigen. Even if the antibody is no longer detectible, the red cells of all subsequent transfusions to that patient must lack that antigen, to prevent a secondary immune response.
Once an alloantibody has been identified in a patient, it is helpful to demonstrate that the patient's red cells are negative for the corresponding antigen. Only patients negative for the offending antigen could possibly develop an alloantibody against that antigen.
Each individual commercial antiserum comes from the manufacturer with a package insert that includes a detailed procedure for the use of the product. It is necessary to retain the package insert with the vial of commercial antiserum until that vial is exhausted. This package insert is used as the procedure for this product. Each reagent package insert must be read prior to testing to ensure the correct procedure is used. The package insert is retained for five years.
Note: The reagent supplier is discontinuing the enclosure of the package insert with the product. The instructions for product use is printed from the internet and found in the designated rare antisera section in Blood Bank.
Certain antigen typing sera may at times be impossible to stock in the transfusion service. With the pathologist's approval, crossmatch compatible blood may be the only antigen screening viable.
Special typing of donor units may not be necessary for certain antibody specificities. Anti-IgG crossmatching with the patient's plasma may be all that is necessary for antibodies that characteristically react below 37°C (e.g.: Anti-M, P1, A1). These antibodies do not ordinarily elicit an anamnestic response to the transfusion of antigen positive red cells. Blood can be selected without antigen typing for transfusion to patients with anti-Lewis a (Lea) or anti-Lewis b (Leb) because these antigens are not intrinsic to the red cell and delayed transfusion reactions are not a concern.
IV. Quality Control:
Note: Blood grouping reagents are remarkably stable, often giving satisfactory results after many years of storage. The product manufacturers are required by FDA to limit the expiration date to no more than two years. Because it is sometimes difficult to procure commercial rare antiserum, it is acceptable to utilize expired reagent antiserum as long as appropriate controls have been run in parallel with the tests.
Each day of testing both a positive and a negative control must be successfully tested for each reagent used. The testing of each reagent (including the expired reagents) must exhibit at least a 2+ reaction for the positive control and zero for the negative control. The manufacturers' package insert procedure must be followed exactly when using commercial antiserum.
1. AABB Technical Manual, current edition.
2. Modern Blood Banking and Transfusion Practices, Denise Harmening; 1989; pp252-253.
i. September 2002 M. Burger
June 2010 B. Wiley (Revised: II.note added)
September 2011 R. Tugade (no changes)