Which of the following represents the best pair of screening cells for ABO/Rh testing?

Which of the following represents the best pair of screening cells for ABO/Rh testing?

• A. Cell 1: Group O, D+, C+, c-, E-, e+, K+, Fy (a-b+), Jk (a-b+), M+, N-, S-, s-; Cell 2: Group O, D+, C-, c+, E+, e-, K-, Fy (a+b-), Jk (a+b-), M-, N+, S+, s-
• B. Cell 1: Group O, D-, C-, c+, E+, e-, K-, Fy (a-b+), Jk (a+b+), M+, N-, S+, s+; Cell 2: Group O, D+, C+, c-, E-, e-, K-, Fy (a+b-), Jk (a+b-), M-, N+, S-, s+
• C. Cell 1: Group O, D+, C+, c+, E+, e+, K+, Fy (a+b+), Jk (a+b+), M+, N-, S-, s+; Cell 2: Group O, D-, C-, c+, E-, e+, K-, Fy (a+b-), Jk (a+b+), M+, N+, S-, s-
• D. Cell 1: Group O, D+, C+, c-, E-, e+, K+, Fy (a-b+), Jk (a-b+), M-, N+, S-, s+; Cell 2: Group O, D+, C-, c+, E+, e-, K-, Fy (a+b-), Jk (a+b-), M+, N-, S+, s-

Answer: (D)

Screening cells for an antibody screen are chosen to maximize the chance of detecting clinically significant alloantibodies while avoiding interference from ABO blood groups. Using group O red cells helps prevent ABO antibodies from giving false positives or masking other antibodies. Having two cells that differ across a broad range of antigens—so that one cell expresses an antigen that the other cell does not—allows you to see a pattern of reactivity that points to the specific antigen(s) the patient’s antibodies are targeting. In this pairing, both cells are D-positive, which helps ensure that anti-D antibodies, if present, can be detected, while still relying on the red cells’ broad antigen variety to catch antibodies against other common antigens. The first cell expresses K, Fy(a−, Fy b+), Jk(a−, Jk b+), M+, N−, S−, s−, and the second cell lacks K but expresses Fy(a+), Jk(a+), M+, N+, S+, s−. This means the two cells cover differences in Kell, Duffy, Kidd, and MNS antigens (as well as S/s), giving complementary profiles. If a patient has an antibody against any of these antigens, at least one screening cell will react, making the antibody detectable and aiding subsequent identification and compatibility decisions. Other pairings tend to offer less antigen diversity or mix antigen expressions that reduce the ability to distinguish which antigen is causing reactivity. This pair provides the broadest, most informative antigen coverage among commonly encountered clinically significant antibodies, making it the best choice for screening.

Screening cells for an antibody screen are chosen to maximize the chance of detecting clinically significant alloantibodies while avoiding interference from ABO blood groups. Using group O red cells helps prevent ABO antibodies from giving false positives or masking other antibodies. Having two cells that differ across a broad range of antigens—so that one cell expresses an antigen that the other cell does not—allows you to see a pattern of reactivity that points to the specific antigen(s) the patient’s antibodies are targeting.

In this pairing, both cells are D-positive, which helps ensure that anti-D antibodies, if present, can be detected, while still relying on the red cells’ broad antigen variety to catch antibodies against other common antigens. The first cell expresses K, Fy(a−, Fy b+), Jk(a−, Jk b+), M+, N−, S−, s−, and the second cell lacks K but expresses Fy(a+), Jk(a+), M+, N+, S+, s−. This means the two cells cover differences in Kell, Duffy, Kidd, and MNS antigens (as well as S/s), giving complementary profiles. If a patient has an antibody against any of these antigens, at least one screening cell will react, making the antibody detectable and aiding subsequent identification and compatibility decisions.

Other pairings tend to offer less antigen diversity or mix antigen expressions that reduce the ability to distinguish which antigen is causing reactivity. This pair provides the broadest, most informative antigen coverage among commonly encountered clinically significant antibodies, making it the best choice for screening.