Chapter 19: Blood Component Therapy

I. BLOOD BANKING PROCEDURES

1. Type and screen. Whenever possible, serum or plasma samples from both mother and infant should be obtained for initial ABO group and Rh(D) type determinations.

   1. Investigations of the maternal sample should include:

      1. ABO group and Rh(D) type.

      2. Screen for unexpected red cell antibodies by an indirect antiglobulin technique (IAT).

         1. Unexpected (or atypical) red cell antibodies are clinically significant allogeneic antibodies (alloantibodies) other than the isohemagglutinins, anti-A and/or anti-B, whose presence may be expected depending on the ABO group.

         2. If possible, review maternal antenatal records regarding antibody evaluations.

   2. Investigations of the infant (or umbilical cord) sample should include:

      1. ABO group and Rh(D) type.

      2. Direct antiglobulin test (DAT) performed on neonatal red cells.

      3. In the absence of maternal serum or plasma, the infant’s serum or plasma is screened for unexpected antibodies by an IAT.

         1. Infants very rarely make alloantibodies during the first 4 months of life, but they may have maternal alloantibodies acquired transplacentally.

         2. Repeat ABO group and Rh(D) type determinations may be omitted throughout the remainder of the neonate’s hospital admission or until age 4 months is attained, whichever occurs sooner.

      4. If a non–group-O neonate is to be transfused with non–group-O erythrocytes, which are incompatible with the maternal ABO group, then the neonate’s serum or plasma must be tested for anti-A and anti-B using an IAT. If either antibody is detected, then donor erythrocytes that lack the corresponding antigen must be chosen for transfusion.

2. Type and cross-match red blood cells

   1. Perform an initial screen for unexpected (or atypical) red blood cell (RBC) antibodies.

      1. Test donor candidate red blood cells against infant’s serum or plasma (from umbilical cord [preferred] or venous blood) and inspect for agglutination and/or hemolysis after incubation at 37°C (98.6°F).

      2. Alternatively, if mother and neonate are ABO compatible, then maternal serum or plasma may be used (to limit neonatal venipunctures).

      3. If this initial screen for red cell antibodies is negative, then there is no need to perform cross-matching during the remainder of the neonate’s hospital admission or until age 4 months is attained, whichever occurs sooner. If the initial screen for RBC antibodies is positive, then additional testing must be done.

   2. Perform tests to determine the specificity of any antibodies identified.

      1. Using an indirect antiglobulin technique, test maternal or infant serum or plasma against a panel of group O reagent erythrocytes of known antigenic phenotype.

   3. Transfused red cells used typically must lack the corresponding antigen(s) and be compatible by antiglobulin phase cross-match with maternal or infant serum or plasma. In case of antibodies to extremely rare antigens, antigen-typed red cells may not be available, but antiglobulin phase cross-match must still be compatible.

      1. Cross-matches are needed with each transfusion until antibodies are no longer demonstrable in the neonate’s serum or plasma.

      2. The presence of multiple antibodies increases the difficulty of identifying compatible donors and delays blood availability.

II. ROUTINE BLOOD DONATION

1. Voluntary blood donations. These are from donors with both ...