Transfusion service (TS) laboratories use different protocols to exclude antibodies. For example:
- Some laboratories will exclude antibodies that exhibit dosage based on a negative reaction with one homozygous cell.* Other laboratories require negatives with two homozygous cells to increase the confidence that the antibody is not present.
- If a homozygous cell is not available, some laboratories exclude such antibodies based on a negative reaction with two heterozygous cells.* Other laboratories require negatives with three heterozygous cells to increase confidence that the antibody is not present.
*Homozygous and heterozygous do not refer to the red cells per se but to the red cell donors who are homozygous or heterozygous for the genes that determine the red cell phenotypes.
The antibody exclusion protocol on the right is used in this case study.
