Don’t let me catch you saying something silly like, “The antibody screen was negative, so there were no antibodies!” That is not correct; rather, you should say, “The antibody detection test was negative, so there were no antibodies detected!” This test is not perfect (no test can be), so it is absolutely possible for significant antibodies (especially ones targeted against rare red cell antigens) to go undetected on routine tests.
Two important things to remember about antibody screening:
- Group O red cells are used to avoid interactions with ABO antibodies. Any incompatibility with the screen cells should be due to antibodies other than normally occurring ABO antibodies.
- Antibody screens are done on recipients, as mentioned, but many forget the requirement that they are also performed on every blood donor! Plasma-rich products from donors with significant antibodies cannot be used, but the RBCs may be used if labeled with the antibody specificity (but many hospitals will not accept such units).
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