With the rapid growth of the Rh system, the use of the existing naming conventions became difficult. In the 1960s, Rosenfield and his colleagues proposed a numeric assignment for each antigen that is well-suited to electronic data processing, as displayed in Table 4.
Table 4. Rosenfield Terminology.| Rh Antigen | Rosenfield |
| D | Rh 1 |
| C | Rh 2 |
| E | Rh 3 |
| c | Rh 4 |
| e | Rh 5 |
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.
