What is the most probable Rh genotype of a donor tested positive with anti-D, anti-C, and anti-c?

A donor testing positive for anti-D, anti-C, and anti-c likely has the Rh genotype R1r. This can be understood by examining the specificities of the antibodies present and the corresponding genotypes that produce them.

The presence of anti-D indicates that the donor has the D antigen, which is characteristic of genotypes that include either R1 (D and Cc) or R2 (D and CC) alleles along with a corresponding allele that would not express D, such as 'r' or 'r' inherited from the second parent. The presence of both anti-C and anti-c suggests that there is heterozygosity for the Cc antigens.

In this case, genotype R1r (which includes D, C, and small c antigens) is consistent with anti-C and anti-c antibodies, confirming that the donor carries the C and c antigens that the antibodies are targeting.

Other genotypes do not align with all three positive antibodies. For instance, R1R1 would not yield anti-c or anti-c antibodies, R0r would not yield anti-C, and R2r would not account for anti-c without also presenting an anti-C response. This makes R1r the most compatible