Once an antibody hypothesis is generated, most laboratories will select additional cells to rule-out any other commonly encountered antibodies that could not be ruled-out with the initial antibody screen and panel. Cells should be selected that are negative for the antigen(s) that correspond to the hypothesized antibody and positive for the antigen (s) to commonly encountered antibodies that have not been ruled out. If not ruled-out most laboratories will select cells for at least the following: anti-D, anti-C, anti-c, anti-E, anti-e, anti-K, anti-k, anti-Fya, anti-Fyb, Anti-Jka, anti-Jkb, anti-Lea, anti-Leb, anti-P1, anti-M, anti-N, anti-S, and anti-s.
Antibodies to antigens of very low incidence (for example, anti-Jsa) are generally not eliminated in initial testing, but in most settings it is not feasible to try and find rule-out cells. In these cases, it is important for the technologist to understand that these antibodies HAVE NOT been ruled-out due to limitations in the test system.
