The selected cells should be antigen-negative for the antibody that you think is present and antigen-positive (homozygous) for what you are trying to rule out. You are designing a panel that addresses your testing needs.

Example: Jk^b

If you suspect that your patient has an anti-Jk^b and further rule out cells are needed, then those rule out cells should be negative for Jk^b. In the table below, donor cells 1,2, 4, 6, 9 and 10 may be used when creating a select panel to test the patient and help rule out the remaining possible antibodies.

The homozygous rule applies when choosing which cells to use for testing (antigens highlighted in light-yellow).

Example: Picking cells to rule out C

Use panel cell 1 and panel cell 2 (C is in the homozygous state).

Explanation: Panel cells 1 and 2 do not contain the antigen Jk^b (signified by "0" on cell panel). If these cells are tested with the patient's plasma and the reaction is negative, it can be assumed that the patient does not have an antibody to C. C is now ruled out because there would be a total of 3 negative patient reactions with C positive cells (These two reactions and screen cell I from the antibody screen, shown again below).

This should be done for all clinically significant antibodies that you were unable to rule out on the first panel.