17: Blood Component Therapy

I. BLOOD BANKING PROCEDURES

1. Type and screen. Whenever possible, 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).

   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.

      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.

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

2. Type and cross-match red blood cells (RBCs). Mix donor RBCs with maternal or infant serum or plasma (or both) and inspect for agglutination and/or hemolysis after incubation at 37°C (98.6°F). Infants very rarely make alloantibodies in the first 4 months of life. If the initial screen for red cell antibodies is negative, then there is no need to perform cross-matching during that period (or throughout the remainder of the neonate's hospital admission, whichever occurs sooner). If the initial screen for red cell antibodies is positive, then additional testing should be done.

   1. Perform testing to determine the specificity of any antibodies identified (involves reaction of maternal serum or plasma and/or umbilical cord serum or plasma against a panel of reagent erythrocytes of known antigen phenotype).

   2. Transfused red cells used must lack the corresponding antigen(s) or be compatible by antiglobulin cross-match until such antibodies are no longer demonstrable in the neonate's serum or plasma. 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 screened donors with a negative history for potentially blood transmissible diseases. All blood donors are tested using serological enzyme immunoassays (EIAs) and nucleic acid amplification testing (NAT) for viral risks that include HIV (1 and 2), hepatitis viruses B and C (HBV and HCV), human T-cell lymphotrophic viruses (HTLV [I and II]), and West Nile virus (WNV). The only screening assay for parasites currently is an EIA for antibodies to Trypanosoma cruzi (cause of Chagas disease). In addition, EIA or microhemagglutination testing for Treponema pallidum (syphilis) is still required. Testing obviously is not performed for all blood-borne threats; testing for the following viruses is ...