With the rapid growth of the Rh system, use of the existing naming conventions became difficult. In the 1960's, Rosenfield and his colleagues proposed a numeric assignment for each antigen that is well-suited to electronic data processing. D is Rh1, C is Rh2, E is Rh3, c is Rh4 and e is Rh5. Using this terminology phenotypes are described based on the presence or absence of a particular Rh antigen as shown in the example below:
Testing results: D+, C+, E+, c negative, e negative
Rosenfield designation is Rh: 1, 2, 3, -4, -5
If the same red cell sample had not been tested for the c antigen, the phenotype would be written in Rosenfield terms as Rh: 1, 2, 3, -5.
