Background and Introduction to the ABO System
Table 2: Testing the Patient Red Cells with Known Antisera (Forward Typing)
In routine practice, specially prepared blood grouping sera containing anti-A, anti-B, (and optionally anti-A,B) are used to identify the four types of red cells. These sera will agglutinate cells with the corresponding antigen. This is called forward typing.
| A | 4+ | 0 | 4+ |
| B | 0 | 4+ | 4+ |
| O | 0 | 0 | 0 |
| AB | 4+ | 4+ | 4+ |
